It's because Sam's bored, really. They've been pouring over lists of places Bucky could be for days, and Sam's bored of it. He needs something new.
By the tired look on Steve's face, so does he.
"Alright," Sam says one day, at they're sitting at Sam's table, looking up flights to Europe. "Give me your list."
Wordlessly, Steve pushes over the list he had been looking over — a list of places that meant something to him and Bucky. Sam pushes it aside.
"Not this list. Your list of twenty-first century things you need to research," Sam explains. "You were carrying it when we first met."
Now Steve looks up. He gives a little laugh, still looking tired, and runs his fingers through his hair.
"Why?" he asks, bringing a little notebook out from his pocket anyway.
Sam smirks as Steve slides it over to him.
He picks it up and flicks it open, reading the list there.
I Love Lucy is the first item on the list. Sam considers it for a moment, but that's not really a fun activity they could do — it would be them just sitting around. He passes over Moon Landing and Berlin Wall as well. Sam doesn't want to give a history lesson. Steve Jobs is crossed off already.
Sam's lips curl as he reads the next item.
Perfect.
Disco.
"I'm going to teach you disco," Sam says, tapping his finger to the word. "You need a break from this." Sam gestures to the papers around them.
"Okay," Steve says, giving Sam a small smile. "I'm still not sure what disco is, but okay."
"Time to dance, old man," Sam says.
Steve raises an eyebrow, but doesn't look away from Sam.
Sam quickly opens YouTube and types in 'how to disco' and clicks on the first video that comes up, a video by Ryan Kasprzak.
"Get up," Sam says, making the video full screen.
Steve looks at the video warily, but still stands up, taking his place next to Sam.
The two of them watch the video, dancing along to every single step the instructor gives them and it's honestly the most fun Sam's had in ages. By the end of the video, they're both almost in tears from laughter, and they're busting out every disco dance move given to them.
"And that," Sam says, bending over, "is disco."
"I'm sort of glad I missed that," Steve says in between laughs. As they straighten up, Steve looks happier and more awake than he's had in weeks.
Mission accomplished, Sam thinks.