A routine check-up reveals that the Pilates trainer Kathrin is suffering from kidney disease and needs a transplant. Her husband Arnold is a successful architect in the middle of a large project and is afraid of donating one of his kidneys. Götz, a friend of the couple's, would undergo the operation immediately if it means saving Kathrin's life - even though this causes problems with his partner Diana. Confronted by issues of life and death, the fragility of the relationships within and between the couples is laid bare. Eventually, the question can no longer be avoided: what is true love?