The fire is going, sherry poured, presents wrapped, and claws are being sharpened. In a seaside cottage perched on a cliff, one family reunites for Christmas.

While snow falls, a tyrannical widowed matriarch presides over her unruly brood. Her niece tends to her whims, but fantasises about eloping; and as more guests arrive, each bringing their secret truths and dreams, the Christmas tree explodes, a brawl erupts, an escape occurs – and their 'midwinter madness' climaxes.