The TARDIS is caught in the magnetic tractor beam of a space salvage ship. Clara (Jenna-Louise Coleman) begs the Doctor (Matt Smith) to fix it, but he says he doesn’t have a big friendly button to fix everything. She spots a device that looks like an egg rolling across the floor and burns her hand trying to grab it. There is a jolt, and they are thrown into darkness.
The Doctor wakes up on the salvage ship, crewed by Gregor (Ashley Walters), Bram (Mark Oliver), and Tricky (Jahvel Hall) van Baalen. The Doctor insists they help him rescue Clara. Bram is killed by an ossified humanoid creature, a kind of time-zombie. The TARDIS traps Gregor, Tricky, and the Doctor in a loop of corridors. The Doctor finds Clara, but the engines are damaged, and they must go to the engine room to stop an explosion.
The Doctor says the ossified creatures are themselves from the future. Gregor and Tricky contact themselves and become the ossified creatures. The Doctor and Clara flee toward the engine. Thinking they don’t have long to live, the Doctor asks Clara who she is and why she died twice. She does not understand.
They find the engine has already exploded, but the TARDIS put the room in time stasis. On Clara’s hand is written Big Friendly Button. The Doctor realizes they must go back and activate the remote control for the tractor beam—the device Clara picked up. He crosses a time rift and gives the remote to his younger self. Time rests and the TARDIS continues on its way. Clara does not remember the conversation with the Doctor.
The episode received decent reviews. Though it was criticized for a bit too much running around, it was considered a lot of big, dumb fun. Fans got to see other parts of the TARDIS, which had not really happened since the revival. They saw the console room, the Eye of Harmony, the library, the Doctor’s workroom, the observatory, the swimming pool, and the Arch-Recon (The architectural reconstruction system). This was pretty much the reason it was written. As a child, head writer Steven Moffat was disappointed in the way the interior of the TARDIS was shown. At one point, there is a time-leak, and we hear many voices from past episodes. Clara reads the Doctor’s name in a book in the library, but with the time-reset, she forgets it.