A small, black cube appears in midair and floats over to rest on a side-table. And the cubes? DOCTOR: And all around the world, people are picking them up and taking them home. DOCTOR: Erase humanity before it colonizes space. HOSPITAL, LIFT, DAY
The DOCTOR, AMY and RORY fall to the floor of the lift as they are forced through the portal. How to destroy a human? KATE leaves. Life with the Doctor was like this --
We are bombarded with scenes of AMY and RORY'S travels with the DOCTOR. POND/WILLIAMS HOUSE, NIGHT
The DOCTOR, RORY and AMY pause outside the TARDIS and look back at BRIAN. RORY: Choose. RORY: Full-time? Real life? So that was the year of the slow invasion, when the Earth got cubed and the Doctor came to stay. The Shakri used the cubes to turn people's hearts off. The cubes. The heart! The ship begins to shake violently. They can't be dying.
Plan: A: the Doctor; Q: Who takes Amy and Rory back as full-time companions? A: the Ponds; Q: Who does the Doctor stay with to investigate the black cubes? A: UNIT; Q: Who does the Doctor leave in charge of the cubes? A: A year; Q: How long does it take for the cubes to start activating? A: random features; Q: What do the cubes suddenly begin activating? A: The Doctor; Q: Who tracks the cubes to the Shakri? A: Shakri; Q: Who wants to eliminate humanity before they can colonize in space? A: an infestation; Q: What do the Shakri believe humanity is? A: the electric pulse; Q: What does the Doctor reverse to destroy the Shakri ship? A: people's hearts; Q: What does the Doctor reverse the electric pulse used to stop? A: Brian; Q: Who urged the Doctor to take Amy and Rory back as full-time companions? Summary: Amy and Rory begin to wonder whether they should choose between normal life and "Doctor life". Many black cubes appear around the world and the Doctor stays with the Ponds to investigate but the cubes are inactive and the Doctor leaves UNIT in charge. A year goes by and the cubes suddenly begin activating random features before stopping the hearts of one third of humanity. The Doctor eventually tracks the cubes to the Shakri, who plan to eliminate humanity before they can colonise in space, believing them to be an infestation. The Doctor reverses the electric pulse used to stop people's hearts and destroys the Shakri ship. At Brian's urging the Doctor takes Amy and Rory back as full-time companions.