Ben looks for a date to a family wedding; Sara starts worrying that her and Ben are getting too serious; Aaron tries to take his relationship with his girlfriend to the next level.
Sara puts a stop to her and Ben's booty calls when she sets her sight on a new doctor at work. Ben's friend Colleen comes to town and he is determined to get past her seeming reluctance to get physical. Aaron rebounds from his broken heart by setting his sights on Riley.
Ben and Fitz try to cheer Aaron up with a guys night out when he learns of his ex's engagement only to end up competing for a girl. Sarah tries to get closer to Riley by tagging along on a night out.
When Ben encounters and ex-girlfriend, he discovers she is suffering from short term memory loss and takes advantage. Fitz is surprised with his lesbian mother's new lover.
Sarah tries to change her casual relationship to a serious one while Ben tries to break it off with a girl who is very clingy. Fitz and Aaron fight over money.
Sarah asks Ben buy her in a charity bachelorette auction so that she doesn't end up with a nerdy guy who has promised to bid for her. Ben keeps messing up cool catch phrases until he ends up being charged with harassment. Fitz decides to go wild one last time before settling down with the girl of his dreams but a photo of him with another woman ends up on the Internet.
Sarah reluctantly heads home for her sister's baby shower and takes the gang with her on a mini-vacation to Mardi Gras. Aaron overindulges in alcohol and cuts loose with a woman he mistakes for Riley.
Aaron finds out that a girl he mentored years ago is a successful star in adult films and he feels he has failed her. An older doctor that Sarah admire falls for Riley and puts Sarah in an awkward position as a go between. Ben and Fitz try to assuage their conscience when a friend is in the hospital and end up in a competition to impress the man's girlfriend.
Sarah's latest guy is a blind man and she discovers she misses being complemented on her beauty. Ben's latest girl is always wearing a hat which drives him to distraction. Aaron finds a cougar while Fitz dates her daughter.
Both Sarah and Ben lose themselves when they reunite with old flames. Aaron shocks Riley by going out of character and using his wealth to impress women.
Ben decides to go into business for himself and asks Aaron to back him. Sarah's new guy proves to be a challenge romantically due to his medical condition. Fitz is determined to improve his standing on Chicago's most doable bachelor list and enlists Riley to help him.
Sarah's dedication to her new boyfriend leaves Ben alone and wanting her back, leaving him in a slump of his own regarding personal relationships. Riley meets someone special, but their future is uncertain due to his cryptic revelation.
Sara and Ben agree to a double date with other people - elsewhere Fitz and Aaron formulate a plan to get rid of Riley's new boyfriend.