"Oh! Dinos!" The little boy in his arms shouts in awe. They were standing in front of the giant T-Rex replica in the lobby of the Natural History Museum; hadn't even gotten to the good stuff yet.

"What do you see, Wyatt?" Rick asks his grandson, trying to see the world through the two year-old's eyes.

"Dinos!" he points again.

"That's a pretty big dino, huh?" Castle continues, walking towards the information desk.

"It a big dino," Wyatt nods, not taking his eye off the prehistoric beast.

Castle had offered to watch Wyatt when his mother got called into work unexpectedly and his father was on a field trip with his older sister. What better way to spend a cold, snowy February day than getting lost in the museum? Just like he had done when Alexis was Wyatt's age.

"Hi!" The kind woman at the desk smiles at him. "What brings you today?"

"Dinos!" Wyatt shouts.

"Oh my goodness! Are you two on a Dinosaur hunt?"

"Say 'Yes!'" Castle prompts, bouncing the boy in his arms.

"Yes!" Wyatt echoes.

"Well I hope you find some," the woman smiles again, passing Rick a handful of pamphlets, including a few on the dinosaur exhibit.

"Thank you," Castle nods and the two head deeper into the museum to see what they can see.

They hit up the Africa exhibit first. There's only a handful of other people in the darkened room with them. A school group in their navy and red uniforms, traveling around with their knapsacks in two lines; a mother with her three kids, one right around Wyatt's age; and a few others that pay no mind to the throng of children filling the room with noise.

Wyatt is immediately frightened by the large animals in front of him and buries his face in his grandfather's neck.

"Oh, buddy," Castle murmurs. "It's alright." He smooths a hand down the boy's back, talking to him quietly.

The man next to them, heavyset with a large mustache, wearing jeans and a green polo, chuckles at them and gives Castle a look to say 'I've been where you are, buddy.'

"Wyatt, look," Castle starts, turning so the toddler can see the animals again. But Wyatt is having none of it, hiding in his shoulder once again. "These animals are pretty big, huh?"

"They big," Wyatt says. "Scary."

"They are kind of scary, yeah."

"Dinos! See the dinos, gran'pa!"

"We're gonna see the dinos soon, bubby."

They make quick work of the Africa room, and bypass all the others like it. Though Wyatt does like looking at the bigger kids on their field trip, and comments on how they are just like his older sister

Instead they head upstairs to the section of the museum where the traveling exhibits are always held.

The wall of sound that hits him as he steps off the escalator, Wyatt stumbling next to him, lets him know this is the place to be for most of the school groups in the museum that day.

Grossology: An adventure into everything gross and icky. Boogers, vomit, gross smells; a paradise for a tween-age boy.

"Oh! Look Gran'pa!"

And apparently his two year-old grandson.

"I see, buddy," Castle nods, letting the toddler drag him across the room to the display he saw.

The two tore through the room. Seeing everything that could be seen; touching everything that was to be touched. Wyatt learned a hard lesson it 'waiting your turn,' and Rick Castle's patience was tested just a bit.

Rick took a secret video of Wyatt playing with the 'fart sounds' machine and dying with laughter, his green eyes alight with joy, and sent it to the boys' parents and to his wife, who was stuck in meetings all day. The kids behind Wyatt in line were also laughing, and egging the toddler on.

"Preston! Brock! Leave him alone!" Their teacher called to the boys, pushing them away from Wyatt and the fart machine. "Sorry," she says to Rick.

"Boys," Rick answers with a shrug and a half smile. He gives his grandson another minute to play before calling him over. "You ready to go find the dinos?"

"Yes!" Wyatt's cheer could be her perfectly clearly over the noise in the room.

"Alright, let's go," Rick smiles and waves to the teachers and chaperones accompanying the school groups in the room as they walk. And one escalator ride and a walk down a hallway later they reach the coveted exhibit.

It's instantly darker once they step into the exhibit. The browns and greens of the room are a drastic difference from the purples and neon of the area they were just in.

The dinosaur exhibit goes through the history of pre-historic creatures. From the giant water bugs and trilobites into early dog and bird like creatures until it finally reaches the age of dinosaurs.

Rick reads everything to Wyatt, telling the story in a way the toddler will understand. And Wyatt hangs on his every word; staying almost completely silent in his arms.

"Dinos!" Wyatt is completely entranced by the room, going from display to display asking over and over again: "What's this?"

They spend the longest time in front of the Triceratops (Wyatt's favorite), and the kind staff member in the room squats down to Wyatt's level and gives the excited and interested little boy all the dinosaur facts he could ever want.

Then, as if his own private paleontology lesson wasn't enough, the staff member, whose name is Jason and he has three sons of his own, brings out 'real' dinosaur bones and footprints for Wyatt, and a few other kids who have gathered, to see and touch.

The final exhibit they visit, inspired by Wyatt's love of the movie Toy Story, is the room all about space. Rocket ships, the planets, more things to be touched; Wyatt grew to love it when his grandfather mentioned it was just like Buzz Lightyear. The two made a lap around the room, but it didn't last very long. Naptime wasn't very far off. Though the display explaining electricity with a sparking globe that made whoever was touching it hair stand on end did make Wyatt giggle.

After a trip to the gift shop, where they acquired an armload of dinosaur paraphernalia, including an excavation kit with a dino hidden inside, and a book on ancient Egypt for Wyatt's sister McKenna, their museum trip had come to an end.

Rick straps his grandson into his car seat, and the toddler is asleep before they leave the parking garage.

A/N: Written for Alex's (Castlefanfics on Tumblr) prompt challenge. Hope you guys enjoyed!