THWAP!

Zack’s face stung as a snowball smashed against his cheekbone. He turned toward the culprit to see his big sister firing snowballs like a crazy person. ZIP! ZIP! Two more snowballs whizzed by his head and Zack ducked to avoid them. “Ha! Right in the face, little bro! Stings, don’t it?”

Zack wiped the wet slush from his face. “Not cool, Zoe.”

Zoe sidled up next to her brother and put her arm around him. “Come on, Zacky-poo, what fun’s a snowball fight if you can’t drill your little brother in the face?” She pulled a snowball out from behind her back and smashed it into Zack’s mouth.

“Zoe!” Zack squirmed away and spat out the snow. “You’re so annoying.”

“All right, you guys, chill out. We’re almost there,” Ozzie said, pointing to the Canadian shoreline on their left. “So here’s the plan. We’re going to have to get close enough to the riverbank to jump off before the current gets the best of us.” Ozzie threw his oar to Rice. “You and Zack guide this thing to that side.”

“Aye-aye, cap’n,” Rice said, taking the oar. Zack and Rice moved to opposite sides of the ice raft and began paddling with the current. But before they could gain control of their course, the floe struck a string of three orange-and-white buoys.

BAM! BAM! BAM! The floe careened off each buoy, spinning cockeyed in the water.

“Come on, guys,” Zoe screamed, her balance a bit wobbly. “Start paddling better!”

“We’re trying,” Zack and Rice both called out simultaneously.

“Look out!” Madison cried, pointing behind them to the zombies. “They’re almost—”

WHAM! The zombie-infested iceberg plowed into them from the rear with a powerful clunk. The two ice floes locked together, and the zombies staggered toward Zack and the gang like a crew of undead pirates laying siege to a ship.

Ozzie whirled around to face the brain-guzzling mutants. “Rice, quick, toss me the nunchaku!”

Rice reached behind his backpack and detached Ozzie’s prized nunchaku. He gave Ozzie his best underhand toss, but it was way too high. The nunchaku sailed over Ozzie’s head, catching a glint of early-morning sunshine piercing through the storm as they plunked into the river.

Ozzie’s eyes went wide with horror.

“Arf-arf!” Twinkles chirped, and started running after the thrown object as any puppy would.

“Twinkles!” Madison shrieked and dove across the ice for her precious pup, who had put on the brakes too late and was sliding across the ice into the rollicking river. Madison nearly dropped over the side, too, but Zoe snagged her by her ski before she could. Madison now dangled headfirst off the edge of the floe, splashing in the freezing cold water. “Twinkles!”

“Zack, help me!” cried his sister. “She’s slipping!”

Out in the cold dark rapids, Twinkles dog-paddled frantically.

Zack quickly brought his oar out of the water and hustled over to grab Madison’s other ski. Zack and his sister hung on to Madison’s feet for dear life and tried to pull her back to safety.

“Twinkles, come back!” Madison cried, lunging again as the current swept her puppy farther out of reach. She sobbed and wailed, half in and half out of the water. She was still reaching futilely for her puppy when he disappeared in the Niagara’s frigid current. “Twinkles!”

Finally, Madison gave up her desperate attempt to save her beloved pup, and Zack and Zoe began to pull her out when suddenly, a zombie river monster lurched to the surface and did a chin-up on Madison’s waterlogged arm.

“No!” Zack screamed.

The hypothermic undead beast cranked open its mouth wide, stretching a web of thick, infectious mucus between its lips, and then chomped down hard on Madison’s forearm. “Nom-nom-nom!”

“Yowie!” Madison cried in pain, and pulled her arm back as Zack push-kicked the zombie in its face with the bottom of his sneaker, sending it bobbing way away from them. Zoe then hoisted Madison up over the icy ledge and back onto their floe.

“Guys, Madison’s been bitten!” Zack yelled to Rice and Ozzie, who were fending off the last of the zombie stragglers.

Two big zombie oafs sporting red-white-and-blue Buffalo Bills football gear lurched across the floating ice island, their goatees frozen with snot and slobber.

In one swift maneuver, Ozzie swung his leg up in a high kick and chopped it down hard on the collarbone of one of the zombies. As the undead iceman dropped to its knees, Ozzie launched in the other direction and attacked zombie number two with a sharp one-two punch combo.

Rice then blasted one of the frostbitten ghouls right in the kisser. Flecks of frozen slime sprung off its desiccated face and floated through the air in slow motion as the undead beast back-flopped into the river with an enormous splash.

Rice and Ozzie ran over to join Zack, Zoe, and the soon-to-be-zombie Madison, who was sprawled out in a state of shock, taking slow, deep breaths.

The river rushed audibly, drowning out the gurgling moans of the zombies bobbing in the quickening current.

“We gotta get off this river, like, now!” Zoe yelled.

With every second, the roar of the rapids grew louder and louder as the whipping wind whisked them ever closer to the horseshoe-shaped cliff ahead.

“Rice!” Zoe screamed over the wind. “I thought you said we weren’t going to hit the Falls yet!”

“My bad. We must have been going faster than I thought.” Rice shrugged nervously while Zoe glared at him with her signature mean-girl scowl. “It’s okay, we can do this,” Rice said. “We just need to create some kind of leverage. . . . Like this!”

Rice stabbed his oar into the edge of the other iceberg still riding side-by-side with their own. Zack did the same, and Ozzie followed suit with one of Madison’s ski poles.

“One . . . two . . . three!” Ozzie shouted, and they pushed off with all their might. The two ice floes separated, and theirs drifted safely into a mass of tree branches at the edge of the Canadian shoreline. Zoe and Rice jumped ashore first while Zack and Ozzie carried Madison behind them by her arms and legs.

After they unhitched Madison’s skis and set her down, Zack grabbed the binoculars from Ozzie and scanned the river for Twinkles, but all he saw was the water spilling endlessly over the mountainous waterfall.