When Janet (Kristin Scott Thomas) is appointed to the prestigious political post of Health Minister in Britain after endless campaigning and road trips, she hosts an intimate gathering for their friends in the Victorian home she shares in London with her dour husband, Bill (Timothy Spall). 

Janet’s acerbic best friend, April (Patricia Clarkson) arrives and others follow, including April's anti-political humanist life coach boyfriend Gottfried (Bruno Ganz), academic Martha (Cherry Jones), Martha's pregnant partner Jinny (Emily Mortimer), and financier Tom (Cillian Murphy), who carrys a gun and whose wife is delayed.

When Bill drops a bombshell, it sparks a series of revelations that threaten to unravel the party.