The 118 fights an apartment building blaze; Athena's response to an accident call leads to a more sinister crime; Hen performs a risky medical procedure during a televised cooking show; Buck is inspired to reunite with his lost love.

The 118 races to rescue a little girl in a runaway hot air balloon and help with a city power outage caused by a hijacked tree-trimmer truck; Athena's investigation into a serial rapist case puts her life in jeopardy.

The members of the 118 rush to the site of a hit-and-run that leaves a familiar face in critical condition. Meanwhile, with Buck's help, Athena investigates the case of a missing woman last seen in a casino and Josh recalls an emergency in 2006 that led him to become a 9-1-1 operator.

A series of ransomware threats leads to an overabundance of emergencies for the 118, including a medevac helicopter crash at a hospital and an air-traffic control tower system failure. Meanwhile Athena must revisit her traumatic attack when the case of the realtor serial rapist goes to trial, Eddie suffers a health scare and Maddie's postpartum depression worsens.

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.

The members of the 118 race to rescue a man who claims he was carjacked, shot and buried alive. Then, they arrive at a home where the owner thinks her roommate is a ghost, Hen receives a visit from the past, and Athena and family are concerned that Harry is still haunted by visions of Jeffrey.