After the first two planets are a bust, there's nothing left for Cooper and Amelia to do but visit number three, Edmunds. They also plan to send TARS into Gargantua's singularity to gather the data required to complete Brand's gravity equation for the long-abandoned plan A, but in order to ensure that Amelia is free from Gargantua's gravitational pull, Cooper drops his craft into the black hole, ejecting just before it explodes. Cooper then ends up in a mind-melting fifth dimension where space and time are not displayed as humans regularly perceive them, but in a non-linear fashion which Cooper can cycle through at will, apparently having been led there over the course of the movie by the intergalactic beings hinted at from the start.