In the series premiere, America's toughest trainer, Jillian Michaels, reveals a side of her you never knew- devoted mother, supportive partner, and comedy chops. Jillian travels to the U.K. for work, causing strain on her home life, and upon returning to Los Angeles, Jillian is pressured by her friends to marry her long-term partner.

Jillian has to learn to manage several work events without her trusted business partner and has to confront issues with her half-sister; Jillian and her fitness team go to Chicago for a workout convention.

Jillian works with the Clinton foundation to fight childhood obesity before heading down to Florida for her mother-in-law's 70th birthday; Jillian plans a party full of surprises, in order to make it a birthday bash nobody will ever forget.

Jillian attempts to win over her in-laws with strippers and alcohol; Jillian and her partner go to Miami for much needed alone time, but Jillian is confronted about the future of their romantic relationship.

Jillian officiates a wedding and Heidi is hopeful that the experience makes Jillian change her mind on marriage; the two moms take different approaches to dealing with a preschool bully.

Jillian gets a deal with Cosmopolitan Magazine, expanding her empire and proving that she's more than just a fitness guru; Jillian's protégé is put to the test during a live workout; Jillian's long-term partner gives her a marriage ultimatum.