It's Richard's birthday. The big 4-0. He's throwing a party and inviting all his colleagues. Diane is new to the firm, and, delighted to be asked, she's brought along her boyfriend, Nick, who has promised to be the spirit of party itself. There's trifle. Lots of trifle. And nibbles. There's just one problem. Nobody else is coming to Richard's party.
It looks like Diane and Nick are in for a long evening, trapped with their peculiar host and their own worst anxieties. Until, that is, someone does turn up. Someone with a lot of history, and an appetite for revenge.
"Not interrupting anything? I let myself in..."