SPOILER ALERT!! - Kirsten Ross (Catherine Hamilton), a young mother, has been abducted. Luther (Idris Elba) realizes it’s the work of Lucien Burgess (Paul Rhys), a collector and writer of the occult, suspected in the murder of another woman, Grace Allen, 10 years previously, but Burgess was never charged.
Meanwhile, Zoe’s (Indira Varma) partner, Mark (Paul McGann) is beaten up. With relations already strained between Zoe, her ex-husband Luther, Mark automatically assumes that Luther is responsible and reports the assault to his boss, Detective Superintendent Rose Teller (Saskia Reeves). But the culprit is not as suspected, and a further twist emerges as Luther receives a recording of the assault from an unknown source.
To complicate things, Martin Schenk (Dermot Crowley) from police complaints is brought in and, realizing that Schenk is going to suspend him, Luther escapes to buy himself some extra time. On a deadline to find the young mother before it's too late, Luther and Ripley (Warren Brown) work into the night to piece together clues and link Burgess to another murder committed 20 years earlier.
Luther and Ripley's investigation leads them to the canal, where they find Burgess's narrowboat. They discover Kirsten inside. Ripley wants to call it in, but Luther stops him, knowing that Burgess will wriggle out of it once again if they stick to the rules. Episode 3 airs Sunday, October 31st @ 10:00p.m. EST/PST on BBC America.