[s1e19] Compass May 2026

Mac eventually discovers that Frankie is alive; she to hide from someone trying to suppress her groundbreaking scientific research—identifying DNA from cold cases. The episode follows Mac and Jack as they navigate the tunnels beneath MIT to help Frankie finish her work while evading a killer. Key Story Beats & "Hacks"

If you are looking to develop this specific plot further, common fan theories and follow-ups focus on: [S1E19] Compass

: To help Frankie process DNA samples while on the run, Mac creates a DIY centrifuge using common items like a bicycle wheel or salad spinner—noted as one of the best "hacks" in the series. Mac eventually discovers that Frankie is alive; she

: Jack breaks his arm in a trash compactor at the beginning of the episode. This occurs because Mac tells him to hold a pipe "perfectly normal" (a physics term meaning perpendicular), which Jack misunderstands. : Jack breaks his arm in a trash

After hearing that Frankie died in a lab fire, Mac travels to MIT with , who is on mandatory medical leave with a broken arm. Their investigative instincts kick in when they notice a suspicious man at the memorial and learn that Frankie's supervisor also recently died in a mysterious car crash.

: Frankie’s DNA research could be linked to future "Phoenix Foundation" cold case files or Mac's own family history.

: Mac creates an electric whip from a cut extension cord to defend the team against the gunmen pursuing Frankie.