how, or when, or from where (слэш)

Jiang Cheng sucks in a sharp breath. “What year do you think it is, Wei Wuxian?”
“2001,” Wei Wuxian says, and then cracks up when Jiang Cheng’s eyes widen in alarm. “Calm down, I’m just kidding. I know it’s 2014.”
Jiang Cheng stares at him.
Wei Wuxian is quiet for a beat. “I presume from your reaction that it is not actually 2014.”
“No,” Jiang Cheng says softly. “No, it’s not.”
(Or, the one where Wei Wuxian loses his memories, and tries to figure out why he isn't dating Lan Wangji yet.)