When “9-1-1” Season 5 returns from hiatus Monday and reunites with its spinoff “9-1-1: Lone Star” in back-to-back time slots, leading lady Angela Bassett will be pulling double duty as her character Sergeant Athena Grant appears on the Fox first-responder drama and has a brief crossover appearance on “Lone Star.”

“There’s a thing called SWAT-ing, where somebody calls 9-1-1, and they send the police or usually a SWAT team to a house,” showrunner Tim Minear tells Variety, teasing the episode. “It’s a malicious prank, and gamers do it to each other. In California, people have died in these raids. So I always thought that would be a fun way to do a crossover because usually it’s cross-state. So we have a story on ‘Lone Star’ where there is a SWAT-ing incident and somebody is killed, and Carlos (Rafael Silva) and Grace (Sierra McClain) feel personally affronted because they were used as weapons. They are trying to figure out where the SWAT-ing call came from, and they trace it to Los Angeles.”

On Monday’s “9-1-1,” Athena, Bobby and the 118 “speed” to the rescue to save a family whose pick-up truck has been rigged with a pipe bomb which will detonate if the vehicle slows under 55 miles an hour, per Fox. Meanwhile, Eddie has a rough transition into his new job, Buck makes an impulsive relationship decision, and Hen is reluctant to accept her new partner in Chimney’s absence in the “Outside Looking In” spring premiere episode of “9-1-1.”

“9-1-1” stars Bassett as Athena Grant, Peter Krause as Bobby Nash, Jennifer Love Hewitt as Maddie Kendall, Oliver Stark as Evan “Buck” Buckley, Kenneth Choi as Howie “Chimney” Han, Aisha Hinds as Henrietta “Hen” Wilson, Ryan Guzman as Eddie Diaz, Corinne Massiah as May Grant, Marcanthonee Jon Reis as Harry Grant and Gavin McHugh as Christopher Diaz. Guest cast for Monday’s episode include Arielle Kebbel as Lucy Donato, Brad Durfee as Jonah Greenway, Anirudh Pisharody as Ravi and Megan West as Taylor Kelly.

Here’s the official description for Monday’s “9-1-1: Lone Star”: “Owen and the 126 race to the rescue when Catherine (guest star Amy Acker) receives a package at the governor’s office that may contain a bio-hazard. Meanwhile Grace and Carlos team up to investigate a prank 9-1-1 call that turns deadly in the all-new ‘Prince Albert in a Can’ time period premiere episode of ‘9-1-1: Lone Star.'”

“9-1-1: Lone Star” stars Rob Lowe as Owen Strand, Gina Torres as Tommy Vega, Ronen Rubinstein as T.K. Strand, McClain as Grace Ryder, Jim Parrack as Judd Ryder, Natacha Karam as Marjan Marwani, Brian Michael Smith as Paul Strickland, Silva as Carlos Reyes, Julian Works as Mateo Chavez and Brianna Baker as Nancy Gillian.

Watch a promo for Monday’s “9-1-1: Lone Star” below.