The irrepressible Mim celebrates her 70th birthday by writing a bucket list. Item one: dragging daughter Fran off on the mini-break they never had, at a theme park Fran wanted to visit 30 years ago.

Mim plans to fund her bucket list escapades by returning to her Alma Mater to recover a time capsule of collectibles that she can sell. Fran hopes to meet famous historian Mary Tash at Cambridge but Mim must not let that happen.

Fran and Mim visit the home of cousin Pat the night before the wedding of her daughter Gemma. When they discover that Gemma doesn't want to go through with the wedding Mim and Fran try to help her.

Mim lets slip a crushing deception, and Fran calls an end to the trip, but it looks like time might be running out for Mim to tell Fran the biggest secret of all.