Nathan faces a life-changing moment of truth - the operation to donate a kidney to beloved grandmother Chel. With only three days to go until the transplant procedure, Chel's need to put her affairs in order inspires Nathan to write letters to his family, in case he does not survive the operation. However when it comes to writing to grandfather Tom, Nathan struggles to find the words - and resolves to visit him in prison against Dave's wishes. Meanwhile, Ben reacts badly to Nathan's letter writing scheme - anxiety and concern for his brother manifesting as irritation. Melissa calls Ben on this behaviour, and Ben makes his peace with Nathan before the big operation. Despite his fears, the operation proves successful for Nathan and Chel - and he asks Ben to destroy the letters he wrote for the family - but not before Rachel sneakily reads hers and is deeply touched by the sentiment. Dave likewise is touched by the revelation of flowers sent from Tom for Nathan and Chel - and he vows to give his father a second chance. Meanwhile Carbo's "twitching" date with Solar Panel agent Amy proves to be a disaster. Undaunted he vows to continue the hunt for a wife.