For aspiring British writer Daniel (MATTHEW MacFADYEN), times have been better. Not only has he been in the shadow of his more famous novelist brother Robert (RUPERT GRAVES) who lives in New York, but he and wife Jane (KEELEY HAWES) live with his parents, and Jane is itching to get out, especially since she clashes with her mother-in-law, Sandra (JANE ASHER).
Things have become more complicated now that the brothers' father has died, with friends and family assembling for the funeral. Among them is their cousin Martha (DAISY DONAVAN), who's arrived with her fiancé Simon (ALAN TUDIK), who's never impressed her father, Victor (PETER EGAN).
That's been exacerbated due to Simon accidentally ingesting hallucinogens owned by Martha's drug dealer cousin Troy (KRIS MARSHALL), resulting in Simon being high. That's complicated by Justin (EWEN BREMNER) constantly trying to hit on Martha, while Howard (ANDY NYMAN) isn't happy to be stuck transporting the cantankerous and wheelchair-bound Uncle Alfie (PETER VAUGHAN).
From the funeral home delivering the wrong body to the home for the services to the diminutive Peter (PETER DINKLAGE) showing up with a secret about the deceased, things progressively spiral out of control, with Daniel and Robert having to put aside their differences to deal with the comedy of errors that arises.