Plot: Sheldon puts Jack and Carly in an uncomfortable position when he asks them to provide an alibi for him to keep Stephanie from knowing he was with his wife Marianne, who he's in the process of divorcing! It's a poor alibi, and the three of them end up going rock climbing with Stephanie in order to preserve it. When Steph finds out the truth there is a big blow-up between her and Sheldon and they quit speaking