Bobby meets Athena's parents for the first time and Maddie attempts to end her marriage for good, causing Doug to insinuate himself even deeper into Chimney's life. Meanwhile, a tanker carrying a tiger shark crashes on the freeway and a gas leak in a plastic surgeon's office happens mid-surgery.

When a blimp suffers mechanical failure and its engine catches fire, Athena and the 118 must rescue victims both inside and outside a packed sports stadium. Bobby and Athena drop off May on her first day of college and discuss honeymoon plans, while Maddie and Chimney go to couple's therapy.

The 118 race to the rescue when a structure collapse at a "happiness convention" traps people under rubble. While on FaceTime with her mom, Athena's father suffers a stroke and crashes through the wall of his house. Hen stretches herself too thin with test prep and her new responsibilities at the 118, while Maddie tries to help new recruit get his bearings at the call center.

While in Florida caring for her ailing father, Athena and Bobby investigate the disappearance of her childhood friend from 45 years ago.