The episode starts with a total homage to Grease (seriously) in a previously-unseen outdoor lunch area thing, with the girls asking Mercedes about what really went down between her and Sam the previous summer. She finally cracks and tells them they spent a lot of time together near a lake (just go with it). Meanwhile, the guys are on the bleachers asking Sam the same thing. And, of course, this is the perfect lead-up to a rendition of Summer Nights (intercut with Mercedes, the girls, and Kurt). Title card.