Late September takes place over a 24-hour period, in a beautiful Kent house and garden, and follows the course and aftermath of a birthday celebration organised by a middle-aged woman for her husband to whom she has been married for nearly 40 years. As the day and night progress, old rifts, new relationships and secrets emerge amongst friends, and the underlying tensions in the marriage can no longer be contained.

A teenage boy lives with his single mum in a flat in South London. Into the flat below moves an anti-social, former Rock God who faked his death 8 years ago. The teenage boy works out who the mysterious neighbour is and blackmails him into teaching him the dark arts of Rock Guitar.