As Edgewater celebrates its annual Founders' Day festival, a catastrophic sinkhole opens beneath Main Street, trapping residents underground and forcing Station 42 into a high-stakes rescue. Meanwhile, a mysterious former firefighter arrives in Edgewater.

When a fast-moving wildfire threatens Edgewater, Station 42 and Three Rock battle increasingly dangerous conditions in an effort to contain the blaze. Meanwhile, as Bode works to connect with a newcomer carrying a complicated past, Sharon helps uncover a critical lead in an active investigation, setting the stage for unexpected consequences both on and off the fire line.

As financial pressures continue to mount at Station 42, Bode fights to prove that Edgewater's new volunteer firefighting program can make a difference, and recording artist INK performs at Smokey's Bar.

When escaped convicts trigger a dangerous manhunt, Bode and the Station 42 crew join forces with Sheriff Mickey Fox and her deputies to protect their loved ones and the community caught in the crossfire.