An awkward run-in with her former best friend and her ex inspires Sam to own up to her past mistakes, both emotionally and financially. Meanwhile, as she resets her relationship with her mom, Sam is horrified to learn Carol is dating.

Sam faces her hardest challenge yet: avoiding alcohol on St. Patrick's Day in Boston. Brit gives Sam an unexpected chance to rekindle their friendship. James and Mindy track down his lost keys while battling St. Patrick's Day temptations.

Sam embarks upon her first terrifyingly personal hook-up as a sober person with the help of Felicia, who has big plans to jump-start Sam’s dating life. Meanwhile, Carol “accidentally” plants a small seed of doubt in Brit’s mind about Joel.

Sam and James travel to New York. While there, Sam is confronted with memories of who she was before sobriety and must decide whether she can risk being Old Sam again. Olivia and Stephanie take an important step in their IVF journey.