The New Era - S2-E4
Plot hole: Early in the episode, Alex tells Seth that the night of the Killers concert is her night off. (She works at The Bait Shop, the concert venue.) At the end of the episode, Alex is paying The Killers, as if she were the manager on duty.
Plot hole: Ryan says that he has left his watch at the motel after sleeping with Theresa, and goes back to get it. However, at the end of The Goodbye Girl (the episode before) he is seen wearing it as he gets out of the car to go and talk to Theresa, only to find she's gone back to Chino. The whole story of Ryan and Seth going back to get his watch from the motel is just an excuse for them to discover the whole Luke/Julie affair.
Answer: She is referring the episode entitled: The Best Chrismukkah Ever, episode 13, season 1. She goes out christmas shopping with Ryan and gets stopped by a security when she is out by Ryan's car. He asks to look inside her bag and finds a stolen watch and some other stolen things.