3. To the Last Man

Tommy Brockless is a young World War I soldier, shell-shocked from his experiences in the trenches. In 1918, Torchwood agents Gerald Carter and Harriet Derbyshire take Tommy from St Teilo's Military Hospital in Cardiff to be kept in cryogenic storage. They leave instructions for future Torchwood members that Tommy will one day be key to saving the world. In the present day it is revealed that Torchwood have kept Tommy in storage for 90 years, releasing him one day a year for a medical check-up.

Whilst Tommy is under day-release, Toshiko elects to keep him company. Whilst Toshiko spends time with Tommy, Jack and Gwen discover that the abandoned Cardiff hospital is showing signs of time distortion, with elements of the 1918 hospital appearing in the present. Meanwhile, Toshiko and Tommy grow closer; after an afternoon in the pub, he kisses her romantically. Upon their return, Jack realises that the present year is when Tommy will be needed: he will have to travel back to 1918 and activate "basically a key" called a Rift Manipulator to close the connection between 1918 and the present and prevent disaster. As Tommy is due to be executed for cowardice three weeks after his return to 1918, Toshiko initially refuses to let him go back. Jack persuades her of the necessity of Tommy's return.

After spending the night together, Toshiko and Tommy return to the hospital as the disruptions intensify, accompanied by Jack. During one disruption, the three witness the 1918 Torchwood team; Jack relays instructions through Tommy for them to take the 1918 version of Tommy into their custody before the older Tommy arrives. Tommy and Toshiko share a goodbye, and Jack briefs Tommy on using the key before he steps back to 1918 during the next disruption. However, when back in the past, Tommy becomes shell-shocked, and is led back to his bed by nurses; he is unable to operate the key in his state.

At Torchwood's Hub, Jack and Toshiko use the Cardiff Rift to project an image of Toshiko into Tommy's mind. Tommy senses some familiarity with Toshiko but otherwise does not recognise her. Despite this, Toshiko is able to instruct Tommy to activate the key, and the distortions at the hospital soon dissipate.