David Mitchell and Robert Webb are back for a fourth series of their brainy but daft sketch show. Find out the correct but confusing way to talk to Caesar; there's a great new way to spot the emotional subtext in TV drama; and there's a man who is very angry about grammar - and he has a gun. Plus there's a chance to meet David's surprising new wife.

Cast: David Mitchell, Robert Webb, Olivia Colman, Paterson Joseph, James Bachman, Mark Evans, Keeley Hawes