Tiger Bay, Cardiff, 1953. A mysterious crate is brought into the docks on a Scandinavian cargo ship. Its destination: the Torchwood Institute. As the crate is offloaded by a group of local dockers, it explodes, killing all but one of them, a young Butetown lad called Michael Bellini.

Fifty-five years later, a radioactive source somewhere inside the Hub leads Torchwood to discover the same Michael Bellini, still young and dressed in his 1950s clothes, cowering in the vaults. They soon realise that each has encountered Michael before — as a child in Osaka, as a junior doctor, as a young police constable, as a new recruit to Torchwood One. But it's Jack who remembers him best of all.

Michael's involuntary time-travelling has something to do with a radiation-charged relic held inside the crate. And the Men in Bowler Hats are coming to get it back.