Alvin spends more time with his new found family which causes tempers to flare between him and Bonnie, with Christy trying to stay neutral. Violet is talked into attending her senior prom but gets a surprise at the dance.
Season 1 Episode 21 of Mom was watched by 7,270,000 viewers, resulting in a 2.20 rating in the 18-49 demographic.
Christy is a waitress at a posh Napa Valley establishment who is four months sober and doing her best to be a good mom and overcome a history of questionable choices. Her sobriety is tested when Bonnie, her recovering alcoholic mom, reappears chock-full of passive-aggressive insights into Christy's many mistakes.
Bonnie joins Christy's already complicated circle of relationships: her handsome, married boss - and lover - Gabriel; the restaurant's hot-tempered chef, Rudy; her pretty, 16-going-on-25-year-old daughter, Violet; her sweet but overly honest son, Roscoe; her irresponsible ex-husband and Roscoe's father, Baxter; and Violet's clueless boyfriend, Luke. Christy tries to remain positive as she pursues her new path in life, but she faces an uphill battle, surrounded by a dubious support system - and a copious amount of dysfunction.