Lindsay's mother becomes involved in a gruesome robbery-murder case. (41:44)

Continued from Chicago Fire "Three Bells," Firehouse 51 enlists Intelligence to help corner the arsonist they believe killed Shay. (42:07)

Intelligence is forced to sort through a complicated web of clues surrounding the murder of a mother and her daughter. (42:54)

Lindsay has her first case with the task force and realizes she needs to call on assistance. Meanwhile Burgess is back on the job, but relegated to desk duty. (41:27)

A routine check on a potential terrorist threat puts Burgess in the hospital and intelligence on the case of a well-planned series of related crimes. (43:00)