Episode 1

The series comes back to a London that looks the same and is somehow worse. A spate of nightmarish murders, seemingly indiscriminate at first, keeps getting more audacious, and Luther has a new partner in DS Catherine Halliday. The two of them are confounded by a tangle of leads and misdirection that looks designed to protect something untouchable, some corruption sitting too high to be reached by a warrant. Somebody with enough pull to keep the case spinning is the real mystery.

Luther is used to fighting killers. This season opener wants him fighting the system too. And the two fights keep getting in each other's way. Gangster George Cornelius is applying his own pressure from the side, the way he always does, and the message is clear: catch this killer, or your neck is the next one on the block.

Neil Cross wrote it, Jamie Payne directed. Wunmi Mosaku's Halliday is the best addition the show has made in a while, a detective with her own instincts who is not afraid to tell Luther when she thinks he is wrong. Patrick Malahide's Cornelius remains the most civilised menace on television, and Enzo Cilenti's Jeremy Lake and Hermione Norris's Vivien Lake bring a whiff of moneyed corruption that suits the season's mood. Lewis Young's William Lucas, Sonita Henry's Daria Shubik, Dermot Crowley's Schenk, Luke Westlake's Lee Peck and Lex Daniel's Ronald Massey round out the board. It is a crowded board, and the episode keeps every piece moving.

The killings themselves are grim even by this show's standards, and the audacity of them keeps climbing. Luther reads the pattern as a message, and the episode does not let him finish the sentence.

It ends with the corruption still shielded and the body count climbing. The season has set its table, and it is not a comfortable one.