The 118 springs into action when a city-wide blackout and a record heatwave causes mayhem in Los Angeles. Meanwhile, Chimney confides in Hen about Maddie's condition, and Athena's worst nightmare comes true.

As the citywide blackout continues to cause mayhem in Los Angeles, Athena races to save her family from a tragedy. Meanwhile, Eddie must make a difficult choice about his future, and Maddie makes a life-changing decision.