When Aaron becomes depressed over an ex-girlfriend getting engaged, Ben and Fitz decide to take him out for a night on the town, only to end up arguing over a girl. Meanwhile, Sarah tries to befriend Riley and her wild lifestyle by hesitantly attending a party that makes her question her conservative ways.

Ben runs into an ex and reaps the benefits of her short-term memory loss. Meanwhile, Fitz fears his lesbian mother is lonely and tries to find her a girlfriend, but is surprised to find that she is already in a relationship. Elsewhere, Riley dates a man with a breast-feeding fetish.

Sarah struggles to get off the "Booty Call Track" and onto the "Relationship Track" with paramedic Evan, while Ben works toward the opposite with a girl he met over the weekend. Back at the loft, Fitz, humiliated by Aaron's extravagant gift on their "Roommate-aversary," tries to take Aaron on a fun, low-cost night out.

In an attempt to avoid a date with a nerdy co-worker, Sarah asks Aaron to bid on her at a charity bachelorette auction. Meanwhile, Ben accidentally uses a suggestive phrase with a co-worker getting himself accused of sexual harassment. Elsewhere, Fitz thinks he's in the clear to spend one last night partying before becoming monogamous, but when he finds out his girlfriend feels differently, he must scramble to cover up incriminating photos from his wild night.

After fighting with her sister, Sara wants to skip a trip to visit her family; Aaron gets drunk and loses his friends.

Aaron learns a girl he mentored in junior high has become a porn star; a doctor bribes Sara for help impressing Riley; Fitz and Ben visit a friend at the hospital.

Sara misses compliments about her appearance when she starts dating a blind man; Ben dates a girl with an affinity for large hats; Aaron spends time with an older woman

Sara and Ben start losing themselves when they fall back into relationships with their exes; Riley is surprised by Aaron's efforts to impress a woman with his money.

Ben asks Aaron to invest in a new business venture; Sarah encounters some obstacles while dating a cute journalist; Riley tries to help Fitz become Chicago's number one bachelor.

Ben realizes he misses the relationship he had with Sarah; Sarah lies to her boyfriend; Riley falls for a guy she just met.