First look at 9-1-1's deadly contagion event with Bobby, Hen, and Chimney in danger: 'They're trapped inside!'

They've faced a giant blimp, a giant bee swarm, and giant waves (both on land and on a boat), but now the first responders of 9-1-1 face something very small — but very deadly.

In a two-episode arc starting next week, the 118 firehouse will grapple with a virus that turns into a contagion event — as revealed in the promo (below) that aired after Thursday's episode of the ABC drama (which was just today renewed for season 9).

The promo starts with Maddie (Jennifer Love Hewitt) taking a call about a fire at a laboratory. When fire captain Bobby (Peter Krause) asks for more information about the lab, he's informed it is "designated for lethal and exotic viruses."

The 118 goes in, but an explosion appears to trap Bobby, Hen (Aisha Hinds), and Chimney (Kenneth Choi) inside. Buck (Oliver Stark) is seen screaming from the roof: "They're trapped inside!"

Athena (Angela Bassett) asks what can be done and is told by a man one can assume is a scientist familiar with the lab's work that, "If we raise the door right now, we risk releasing a very dangerous virus on the public." Meanwhile, Hen appears to be unconscious inside.

These dramatic episodes follow this week's somewhat lighter installment of the action-disaster series, which focused on everyone forgetting Hen's birthday and Eddie (Ryan Guzman) reconnecting with his son, Christopher (Gavin McHugh), in Texas. (Sure, there was that bus hostage situation, but everything turned out fine!)

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The contagion event kicks off with 9-1-1 season 8, episode 14, "Sick Day," next Thursday at 8 p.m. ET/PT on ABC.