It's Thursday night, which in Sheldon's world means that the guys are coming over for pizza. However, Leonard informs him that he's going over to Raj's to hang out with Priya, with Howard most-likely being there as well, so Sheldon is more than welcome to come along. Sheldon does go, but it's just not the same. But what bothers him more is what Amy tells him the night signifies: that Leonard is the nucleus of their group, not him. To prove Amy wrong, Sheldon, on the next night that Leonard says he's hanging out with Priya, Raj and Howard at Raj's place, plans a gathering of his own at their apartment with his new group of mismatched "friends": Stuart from the comic book store, Penny's old boyfriend Zack, and Barry Kripke (with LeVar Burton a probable no show, although Sheldon did tweet him about the gathering). Will either the group at Raj's or the group at Sheldon's have a good time? Meanwhile, Amy and Bernadette take Penny out for a night on the town to make her forget that Priya has taken her place in Leonard's heart.