Gwen runs a 5K in honor of her late husband and everyone turns out to support her. Stacey struggles with a secret she hasn't told Gavin.

Gavin and Stacey accompany Archie on a quest for his lost love. Nessa deals with her dad while Pam finds a date for Gwen.

On the eve of a party at their apartment, Archie claims that his cozy relationship with Stacey has rendered Gavin unfit for the task and insists on taking control.