Okwe (CHIWETEL EJIOFOR) is an illegal Nigerian immigrant who works in a posh London hotel run by Juan (SERGI LOPEZ). Despite being a doctor, the only jobs Okwe can get are driving cabs and running the hotel night desk where he works with doorman Ivan (ZLATKO BURIC) and often sees local hooker Juliette (SOPHIE OKONEDO) passing through.
When he's not working, he hangs out with his Chinese friend, Guo Yi (BENEDICT WONG), who works in the local morgue, and shares an apartment with Turkish immigrant Senay (AUDREY TAUTOU) who's a daytime maid at the same hotel. She's quite skittish about immigration officials and doesn't want anyone to know she and Okwe are sharing a flat, despite nothing romantic happening between them.
Things take an interesting turn when Okwe discovers a human heart in a guest room's toilet. Juan tells him to mind his own business, but Okwe soon uncovers a black market organ donor ring that's being run out of the hotel. In exchange for forged passports and other immigration papers, illegal immigrants "donate" organs needed by sick people.
With immigration officials closing in on both of them, Okwe and Senay attempt to avoid them, all while trying to figure out how to deal with the organ donor ring and its complicated consequences.