Over the past six years, the remains of more than 90 individuals have been recovered from the canals of Greater Manchester - most of them young men. Headlines are now claiming a serial killer may be responsible for their deaths, a story that has caught fire on social media. In this First Cut documentary, former murder detective Tony Blockley reviews the cases of three young men who drowned in the city's canals. Two of them went missing only to turn up dead later, while the third was seen leaving a nightclub with a mystery man who has never been identified. Is the so-called Pusher real or a 21st-century urban legend?