Marriage is complicated. It doesn't always work out. Sometimes there are things you discover about yourself and each other which mean the marriage has to end. Sad, particularly when kids are involved - but all pretty normal.
Normal that is, until there's a murder.
DS Jane Bennett and DI Mike Lockyer are called in to investigate one of South London's most difficult and distressing cases yet - where family and friends come under scrutiny in the hardest of circumstances.