Rosemary's old school friend Dorothy invites the duo to restore the gardens of her beautiful villa on the French Riviera so the property can be opened to the public. The plan arouses bitter hostility among the neighbours and long-held family secrets start to surface, leading to murder.

The green-fingered sleuths are hired to work behind the scenes of a garden makeover TV show, but Rosemary has an accident while standing in for the programme's star and ends up in hospital. Realising someone is trying to sabotage the series, Laura teams up with no-nonsense presenter Quinnie Dorell to catch the culprit.