The Doctor and Rose travel to the year 2012 and land in a museum of extra-terrestrial objects accumulated by the very wealthy Henry van Statten. He's an avid collector - the TARDIS lands on the museum's 53rd floor below ground level - but he's also using alien technology to develop new weapons from which he derives his large income. He's particularly proud of one device he's acquired but has not yet been able to make functional and to the Doctor's horror, it turns out to be a very old and very dangerous enemy from the past.