“Dude,” Marko says as we’re going up the stairs. “That poor kid.”

  Which about summed it up. And since Marissa could tell I felt awful about leaving Kip alone in the library, she let me shower first so I could get back down there while she took hers.

  The foghorns blasted as I was getting dressed, so I knew I’d be missing the sail out of port, but I hurried back down to the library anyway.

  “Hey,” I said, sliding into a chair next to Kip. “Catch me up.”

  First he looks around to make sure no one can overhear. There are quite a few other people in the library, but they’re mostly on the computers, and no one’s near us. And the Puzzle Lady’s gone, so really, there’s nothing to worry about.

  Not that there would be anyway, but obviously Kensingtons are paranoid, so whatever.

  Then he starts raking in all the papers that are spread across the table, going, “I started with a simple substitution cipher.”

  “Like where 1 is A and 2 is B?”

  “Right.”

  “How high do the numbers on the note go?”

  “To 99.”

  “But there are only twenty-six letters.”

  “If you loop the alphabet, it could go on forever.”

  I let out a really intelligent “Oh.”

  “Anyway, that got me nowhere. So I started shifting the origin of the numbers.”

  “So 1 is B and 2 is C … like that?”

  “Right. It’s called a Caesar cipher, and I did it for twenty-six one-letter shifts.” He watches me, waiting for what that means to sink in. And when my eyes have stretched wide enough, he gives a little shrug and says, “I still wound up with gibberish.”

  “Wow.”

  “So I went online and found out about something called an Atbash cipher, which is a Caesar cipher in reverse.”

  “Oh, so A is 26 and B is 25?”

  “Right. And I did that for twenty-six shifts and wound up with …?”

  “Gibberish?”

  He nods. “Then I found out about this thing called a Vigenère cipher.” He fishes through printouts from the computer and shows me a page that looks like a cross between a word search puzzle and a letter graph, where there’s a set of alphabet letters across the top and another set going down the left column.

  “So what do you do with this?” I ask.

  “A Vigenère cipher uses a key word. So I thought maybe that’s what the word on my note was.”

  “You mean the LION with the extra N?”

  “Exactly.”

  I study the big letter grid for a minute, then say, “But … this gives you back letters, not numbers.”

  He frowns. “Yeah. But after you Vigenère cipher it, you can Caesar cipher the resulting letters and—”

  “Whoa! Stop. That is way too complicated. And it seems like the possibilities are endless! I mean, if the first one didn’t work, you’d have to try the shift thingy through the whole alphabet, right? And if that didn’t work, you’d have to try the whole reverse shift thingy!”

  He holds his head and groans, “Exactly! It may also be a polyalphabetic cipher. Plus the notes were written as subtraction problems, so what does that mean? Or are they incremental dividers and not minus signs?” He shakes his head and says, “There’s also deranged alphabet ciphers.”

  “Deranged?”

  “Yeah. Like, rearranged? Where you take the letters of a word and move them to the front of the alphabet, then continue with the alphabet with that word’s letters missing.” He gives a defeated little shrug. “So I tried LIONN and KENSINGTON and KATE and KATHERINE with about a hundred numeric position shifts and wound up with nothing but gibberish.”

  I paw through the pages on the desk and shake my head. “Unbelievable what you’ve gone through to figure this out.”

  “It’s driving me crazy!” he cries, and actually yanks at his hair with both fists, just like you’d see in some cartoon.

  I sort the papers into computer printouts, the code sheet, and piles of scribbled-on pages. Then I tell him, “Okay, let’s back up.”

  He takes a deep breath and closes his eyes for a moment, then nods.

  And out of my big mouth comes, “It can’t be as hard as you’re making it.”

  “Not as—” He grabs for the papers. “What do you know?”

  I slap down the pages and look him right in the eye. “Why would someone put coded notes under doors if they’re too hard to decipher? I’m sure they mean something, but whoever’s done this can’t scare you or extort money from you—or whatever the idea behind them is—if you can’t figure them out!”

  He keeps on gripping those pages, staring at me.

  I keep them slapped down, staring back.

  Finally, he lets go and says, “Then what? And I did start simple.” He rolls his eyes. “It doesn’t get any simpler than a straight substitution.” He slaps the pages with the back of his hand. “And if LIONN’s not a key word, why’s it there?”

  “What if it translates to a number? You know, like the numbers in the code would translate to letters?”

  He blinks at me a minute, then real quick goes through each number’s place in the alphabet and comes up with 12, 9, 15, 14, 14, which he then writes down as one big number, and then as a big number with commas: 129,151,414.

  I sigh and shake my head. “That doesn’t tell us anything, does it? And it’s one digit shy of a phone number.” Then I go back to the paper with the coded message and say, “So the smallest number is 4, and the biggest number is … 99.” I study it another minute, then ask, “Did you check for a pattern? Or any repeats?”

  “Like, frequency?”

  “Yeah. What is the most common letter of the alphabet?”

  “E, I think.”

  “Can you Google it?”

  He jumps up, and while he’s heading over to a computer, I ask, “Can I try to work something out? Look for patterns?”

  “Sure,” he says with a little wave.

  So I take a blank sheet of paper and start tallying up numbers that repeat, and by the time Kip’s back, I’ve got the stats. “So 53 is in here five times. And 7, 16, and 60 all happen three times, and everything else is once or twice.” I look up at him. “What’s the most common letter?”

  “E is number one, T is number two, and A is number three.” And after he’s studied the code paper a minute, he says, “There are also two occurrences of a 53, 60 combination.”

  I nod. “And two 9, 53 combos.”

  He looks at me. “So 53’s our E?”

  “But … we have to figure out what 53 is if you cycle the alphabet, don’t we? Like, 53 would be the first letter, right? Twenty-six plus twenty-six plus one?”

  He sort of stares at me, then a little smile flashes onto his face. “Right.”

  So real quick I make a chart that goes from 1 to 26, then cycle around until I get to 99. Then I take the tally of numbers I’d already done and find out that A, H, and P have the most tallies.

  Which makes me feel like I’ve gotten a whole lot of nowhere.

  So finally I say, “Seems like a total dead end.”

  He shakes his head. “To me, too.”

  “Okay,” I say with a sigh. “Let’s get back to simple.”

  But before we can get back to simple, Darren and Marko walk in. They’re wearing ball caps and old-school Wayfarer glasses, and I can tell Kip actually doesn’t recognize them until he sees Marissa trailing behind.

  “I told you,” Marissa says when they get close. “She’s already totally sucked in.”

  Darren ignores the comment and smiles at us. “Ready for dinner?”

  I grab Kip’s arm and kind of turn him to face me. “Don’t even tell us you’re not hungry.”

  He laughs. “I’m starving.” Then his face falls, and he says, “No. I know what starving is, and I’m not that.” Then he laughs again and says, “But I am really hungry!”

  It’s so weird to see him transform from Deranged Decoder into Hungry T
een that I laugh, too, and say, “Well, let’s go!”

  I start to fold up my paper, thinking I’ll work on it more later, but while Kip hands over my calculator, saying, “Thanks for the loan. Maybe I can borrow it again?” I notice Marissa nudging Darren, and before I can put the paper in my pocket, Darren takes it and the calculator and slips them into his sports coat. “Not tonight,” he tells Kip. “There’s a comedy show and we’re dragging you to it.”

  What’s funny is, Kip doesn’t argue. He just tucks away his papers and follows us to the Schooner Buffet, and during dinner and the comedy show, he even laughs out loud a few times.

  Maybe that’s because dinner with Darren and Marko turned out to be a comedy show all by itself, once Marko whipped out a deck of cards and he and Darren pretended to be dogs playing poker. All the growling and yipping and chomping and snarling … It was bizarre, especially with the Wayfarer glasses, and really funny, especially since they seemed to know exactly what the other one was snarling about.

  So yeah, the night was like a double feature of laughs. And even though I really wanted to ask Kip some basic questions—like how come nobody but Noah seemed to ever check on him, and what he was going to do about the situation with his mother—there was never a good time.

  Especially since Marko seemed to want to keep Kip’s mind miles away from Kensington madness, so anytime there was a lull—like sitting around waiting for Darren to get out of the bathroom, or waiting for the comedian to hit the stage in the Poseidon Theater—Marko gave him drum lessons. There were no drums, but that didn’t stop Marko. First he got his right hand going, tap-tap-tap-tap-tap-tap-tap-tap, then he added his right foot, telling Kip, “That’s your bass drum, boom, boom, boom, boom! Now here comes the snare!” And his left hand started slapping his left thigh. Everything Marko did, Kip copied.

  Marko recruited Marissa and me, too, but we were just sort of extras in the Great Drum Escape—it was Kip he was really paying attention to. And while it didn’t take long for Marissa and me to be like, Okay, enough of that, Kip kept at it everywhere we went.

  Which got annoying!

  Even Darren thought so, ’cause when we were raiding Dessert Island after the comedy show, he finally said, “Can we maybe just eat?”

  Kip stopped slappin’ and tappin’ and said, “Sorry!” but Marko went, “Are you kidding? I wish I had some sticks on me, man. This young dude would be rockin’ right now!”

  So I don’t know—maybe Marko had been right all along. Maybe Kip needed some drum therapy to get his mind off his family and help him through this cruise. All I know is Kip seemed to be a completely different person when we wound our way back down to Deck 9. He even stopped outside our cabins to give Marko a spastic, out-of-nowhere hug.

  At least that’s what I think it was. It happened so fast, and then he was jetting down the hallway toward his cabin, going, “See you tomorrow!” and waving like a lunatic.

  “Yeah, dude!” Marko called after him. “We’ll get you some sticks tomorrow. And maybe you can help us with sound check on Thursday!”

  “Awesome!” Kip called back.

  And it would have been, only sometime during the night, Kip Kensington disappeared.

  TWENTY

  That night my brain must’ve been wrestling with the Kensington code, because I had a weird nightmare where numbers were chasing letters. At first it was like a big swirl of digits and letters, but then the numbers got legs and arms and knives, and became an angry mob, hunting down letters. They had voices, too, and I could hear them yelling, “Get ’em! Get ’em!” but I don’t remember any faces.

  The letters, though, definitely had faces. And no knives. Or legs. My face was in an S, Marissa’s was in an M, Kip’s was in a K, and Darren’s and Marko’s faces were on the top arms of an X. None of us could move. We were just petrified Letter People being attacked by the Number Mob.

  What was weird—well, weirder—was that the knives didn’t hurt. Those numbers hacked away at us, but we were like sponges or something and just sealed back up.

  And then an N appeared with Noah’s face, and for some reason he had a voice and hollered, “Why was six afraid of seven?” into the Number Mob.

  All the numbers stopped and waited.

  “Because seven eight nine!” Noah the N shouted.

  Now, even though the numbers didn’t have faces, it was clear they were all going, Huh? So Noah the N hollered, “Get it? Seven ate nine?” and all at once the Number Mob turned on the number seven.

  Luckily, the phone rang and woke me up from my stupid number wars dream. The curtains were closed tight, so I thought it was deep, dark nighttime, but when I stumbled over to the desk to answer the phone, the clock said it was almost ten in the morning. And I could sort of hear Captain Harald’s voice announcing something over the hallway speakers about us being in Puerto Vallarta.

  I fumbled with the phone before finally getting it up to my ear. “Hello?”

  “Rise and shine, sleepyhead! I’ve booked us on a sailing and snorkeling expedition. Leaves in an hour.”

  “In an hour?”

  “What are you, a rock star? I can’t believe you’re still in bed.”

  “Very funny,” I grumble, because he’s obviously having a good time paying me back for yesterday’s wake-up call.

  Darren laughs. “Wear your swimsuit, flip-flops, shorts, and a T-shirt. And bring a towel. We’ll grab breakfast on our way out.”

  “What’s going on?” Marissa asks after I hang up.

  I stumble over to the balcony and about blind us both when I open the curtain. “Darren booked us on some sail and snorkel expedition.” I open the balcony door, and sure enough, it’s already roasty-toasty outside. “It leaves in an hour.”

  “In an hour?” she says, flinging off the covers.

  So we hustle to get ready, and before you know it, the four of us are heading up the stairs to the Schooner Buffet.

  After one flight, Marissa eyes my feet. “You’re serious?”

  At first I think she can’t believe I’m wearing something besides high-tops, but then I notice that everyone else has their flip-flops under control.

  Mine are wild.

  And loud!

  FLIP-FLAP, FLIP-FLAP!

  And I can’t seem to shut them up.

  “How do you do that?” I ask her, ’cause her feet are just … quiet.

  She gives my feet a little squint. “How do you do that?”

  So yeah, there’d be no sneaking around in these things, but I figured, Who cares? But as we’re cruising the buffet, I spot Lucas and LuAnn over at Fruity Island, and all of a sudden I start caring.

  The first thing I do is look around for JT, because the last thing I want to do is deal with JT. I don’t see him anywhere, but Lucas and LuAnn are obviously uptight. I can’t hear what they’re saying, but from the way they’re putting stuff on their trays and talking to each other in manic little bursts, I know they’re not discussing the fine carving details of the watermelon shark.

  So I turn to Darren and whisper, “Can I borrow your hat and glasses?” and before he can ask me why, I’ve snagged them.

  “Hey!” he says, like I’ve stripped him down to tighty whities.

  “Shhh!” I say back as I shove my hair inside the cap and put on the shades. “Get me something to eat, okay?” Then I abandon my tray and head over to Fruity Island.

  Trouble is, my feet are flippin’ and flappin’ so loud that Lucas actually turns and looks as I walk up. Luckily, he doesn’t seem to recognize me, but they still move away, and the only thing I manage to overhear before they leave is LuAnn saying, “How can they trap us on here? We’re not under arrest!” and Lucas going, “And that’s how we want it to stay! We have to stay cool and be cooperative and just play this thing out.” He takes a deep breath. “At least Noah’s agreed to do what he can to keep it quiet.”

  I do try to follow them over to Pastry Island, but my feet are being so loud that Lucas looks again, so I just head
back to Darren and the others at the main buffet, where my spot’s been taken by three very tan women with tight shorts, silver jewelry, and dainty, manicured feet.

  Cougars.

  And they are definitely prowling around Darren.

  “No,” he’s telling them, “I’m here with my daughter.” He puts a hand on my shoulder as I wedge back into the buffet line. “Family time.”

  “Oh!” they say, and give me the kind of smile that says, Aren’t you cute, and I’d like to kill you, all at the same time. Then they tell Darren, “Can’t wait for the concert!” and leave, carried off by their ridiculously quiet feet.

  The instant they’re gone, Darren snatches his hat and glasses back from me, saying, “Let’s eat and get out of here.”

  Which is what we do.

  And even though Marko says something about wishing “the Kipster” was going with us, Marissa cuts that idea off quick by pointing out that Darren had bought only four excursion passes, so unless one of us wants to stay home …

  Which none of us does. And besides, we’re barely going to make sail time for the excursion as it is.

  No time to track down the Kipster!

  Luckily, we can walk right off the ship and onto the dock, so we don’t have to wait for a smaller boat to shuttle us over. And almost right away we spot a man with a sign that says LOS ARCOS SAIL & SNORKEL. He leads us and a handful of other people off the dock and over to, well, I guess it’s a truck. Or maybe a converted van? The back where we climb in has low sides with posts holding up a bright green canopy, and there are bench seats that go around the perimeter. There’s a big open window between the cab, where the driver is, and the back, where the rest of us are. And once we get going, Mexican music blares from speakers wired through the window.

  Everyone on board seems to be in a great mood, holding on to one of the canopy posts or the side of the truck as we jostle through town and then blast along dusty roads into the countryside. The driver keeps shouting, “Ándale,” as we zoom around cars and people and livestock, so Marko starts shouting it with him, and pretty soon all the adults are going, “¡Ándale! ¡Ándale!”