 However, the most prominent character to redeem himself is Jack's former colleague in the Time Agency, Captain John Hart, who originally appears as a merciless killer in "Kiss Kiss Bang Bang", throwing Jack off a building and forcing the team to help him by threatening to blow up Gwen.However, in his return in "Fragments" and "Exit Wounds", his new attack on the team is revealed to be because he is being blackmailed by Gray to set off bombs throughout Cardiff and capture Jack due to Gray having molecularly bonded a bomb to his skin.With the bomb having been removed, John risks his life to help the team rescue Jack and defeat Gray, subsequently deciding to remain on Earth in the present and learn what Jack finds so fascinating about this time period.

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