 In the episode , alien time traveller the Doctor ( Matt Smith ) takes his companions Amy Pond ( Karen Gillan ) and her husband Rory ( Arthur Darvill ) to the planet Apalapucia for a holiday , but they find that the planet is on quarantine as the two @-@ hearted natives are susceptible to a deadly plague . Amy accidentally gets separated from the Doctor and Rory but when they try to rescue her they arrive 36 years later in her timeline . The older Amy does not trust the Doctor , who is forced to remain on the TARDIS as he also has two hearts , and will not allow the Doctor and Rory to leave and rescue her at the correct point in her timeline . 
