Kate (Clemence Poesy) and Justin (Stephen Campbell Moore) are a successful working couple in their mid-30s whose lives are destined to change forever when the seemingly charming Teresa (Laura Birn) and Jon (David Morrissey) move in to the flat downstairs. Kate and Teresa become especially close when they both discover that they are due to give birth around the same time. But disaster strikes one evening as the couples dine together, which changes everything.