Jack Harkness enters the Doctor's TARDIS and discovers a blue-headed alien who claims to be a regenerated Doctor. The alien gives the game away when Jack notices that he's armed, something the real Doctor would never be. The alien identifies himself as Sao Til, a literal arms dealer who trades in limbs. Jack draws his gun and the two enter into a standoff before...

David Tennant comes in through the TARDIS doors and asks John what he's doing. John introduces Tim Ingham of Stoke-on-Trent, who is pretending to be Sao Til. David then exits the set via the 'fourth wall', pausing briefly before he leaves to chide John for being in "my TARDIS". After a moment of giddiness at having seen David Tennant, John and Tim then carry on from where they left off, resuming their characters and pretending to shoot at each other as they run around the TARDIS set.

博士的塔迪斯被追尾，肇事船居然是泰坦尼克号。原来一家外星旅游公司仿照泰坦尼克号制造了一艘巨大的泰坦尼克号宇宙飞船。

但是飞船却连续遭遇不幸：防护罩被毁，撞上陨石群，船长死去，服务机器人嗜杀成性…