She corners him in the kitchen while he's still putting away groceries, and even with his back turned, she can tell he's smiling.

"Castle!"

He turns over his shoulder, smiles. "Oh, hey."

"What did you do?"

"Got groceries, why?"

Him playing dumb is the last straw for her and it takes every single ounce of self-control in her body to not scream at him. How stupid, impulsive, and childish her husband is.

"Castle! I sent you to Costco for three things and you come home with a bouncy castle!?"

"It's a waterslide, Beckett," he corrects on a facetious laugh.

"As if the name makes a difference!" she throws her head back and slaps her palms on her thighs. "Why did you get it?"

"It was on sale," he shrugs, closing the fridge and finally meeting her eyes.

"Babe! We don't need a waterslide!"

As if summoned by her father's choices (or her husband actively setting the slide up in the backyard), Alexis strides into the kitchen, her face nearly identical to Kate's

"Dad!" she lays into him with a glare made of stone. "What did you do?"

"They bought a waterslide," Kate explains.

"I sent Max with you so you wouldn't get into trouble! And it seems like you got into more."

"Alexis, can I explain?" Castle starts, looking between his wife and his daughter.

"Go for it," she replies.

"You see, it's really very simple. It was the vortex! The Costco vortex! It sucked me and Max in!" He continues on despite the two pairs of rolled eyes in front of him. "We went in with a list and then after we got all that, things just spoke to us! And by the time we checked out, the waterslide was in our cart. And we couldn't just put it back, there were only two left."

"Oh my god," Alexis sighs, her head in her hands.

"Mama!" McKenna shouts through the open screen door. "Mama! Swim! We swim!" The toddler excitedly yells, pointing to the now fully erect slide her aunts and uncles were jumping around waiting for the water to start.

"I see, baby!" Alexis says, putting on a wide smile, opening the door, and picking her up. "What do you say to Grandpa?"

"Thank you!" McKenna stretches out and plants an open-mouthed kiss on Rick's cheek. "We swim, gran'pa? We swim?"

"Yeah," Castle says, scooping up the girl from her mom and heading back outside. "Let's go swim."

"What are we gonna do with him?" Alexis groans to her step-mom, both girls shaking their heads in defeat.

"Make them both clean it up and handle the tears that are bound to come?" Kate suggests

"Deal," Alexis smiles. "Wine?"

"Oh, definitely."

While Alexis goes for drinks, Kate follows the others outside, stopping short on the deck when she sees the blur of a child going down the slide and splashing down at the bottom.

"Mom! Did you see? This is so cool!" Liam calls to her.

"I saw, bubby! It is pretty cool! Did you say thank you to Dad?"

"Yeah!" Liam replies, already back in line for his next turn.

"You guys want to put on swimsuits?" Kate suggests to her fully-clothed children.

"No!" five voices shout back to her.

All Kate can do is throw up her hand in defeat, accept the wine glass Alexis gives her, and watch the chaos unfold.