In Part 2 of the three-part Season 1 finale, the Autobots acquire a surprising ally in their battle to save Earth.

Ben Stiller hosts. Music guest: Foster the People.

Fresh out of prison, Kate Leigh puts a bounty on the heads of Tilly's husband, Big Jim Devine, and her chief henchman, Frank Green, as payback for the murder of Greg Gaffney and the razor attack on Bruce Higgs. In a pre-emptive reprisal Tilly vows to eliminate Kate's muscle before they eliminate hers.

Meanwhile, Kate learns the truth about her son-in-law and is forced to take action that will drive her own daughter away.

Tess Daly and Claudia Winkleman have the results from the first public vote of the series and reveal who will be going home this week.

Birgitte's government prepares to present a new reform package, which is being polished at a political seminar. But when party leader Bjandoslash;rn Marrot comes under a personal media attack, Birgitte senses a rebellion brewing, and the seminar dissolves in chaos. Meanwhile, the tension grows on the homefront where Phillip has a new girlfriend. And Katrine covers the political seminar for Laugesen, but he has his own agenda on the table.

Dermot returns with the results of this week's public vote. The two acts with the lowest amount of votes perform again before the judges decide who to send home.

Two Islamist suicide bombers kidnap the daughter of a valuable MI5 asset. Elena is targeted for assassination, and Harry becomes increasing suspicious of the CIA's deputy-director.

The household is preparing for a concert at Downton in an effort to try and keep spirits up among the convalescing men. Mary is quizzed by Mary about Carlisle, but Mary refuses to answer her questions. She wants to move on with her life without Matthew.