The Undertaker's Gift consisted of a glass casket containing the remains of Francis Morgan, which was hooked to a series of tubes and wires. These tubes were organic and made of corpses of creatures like humans, dogs and Weevils. Francis, though left only with a decayed torso and head, was still alive and unaware of his state. The cables were fused directly into his body and wires were connected to his exposed brain. It produced Antilositic energy and no other energy signatures. (PROSE: The Undertaker's Gift)
The Keshkali were sent back in time to set up the Undertaker's Gift by the Hokrala Corp. In 1919, Corporal Francis Morgan was kidnapped to make part of the bomb. It was set up to activate if the Cardiff Rift was opened enough. For nearly a century it was kept inactive, though it became a rumour amongst Torchwood.
In 2009, Hokrala Corp began sending things through the Rift, causing it to open enough to activate the bomb. The Already Dead started to become active, moving Francis into position. Ray Banks saw the Already Dead and wrote about it on her blog, alerting Torchwood about their location. Gwen Cooper found Ray and her friend Wynnie investigated the building the Already Dead were seen in and helped them investigate. When they tried to do so, Wynnie was killed and Gwen was taken, forcing Ray to try to call in the rest of Torchwood. Jack Harkness and Ianto Jones attempted to save Gwen and shut down the Undertaker's Gift, but they were unable to do so and the Undertaker's Gift was activated. Despite this, a Vortex Dweller was able to save Earth and repair the damage the Undertaker's Gift caused. (PROSE: The Undertaker's Gift)