When Tristan Wood's mistress is admitted in suspicious circumstances, Guy discovers the awful truth about their relationship. Will he do the right thing, even if it jeopardises the launch of his eponymous Neurosurgical Unit?Serena has a one night stand with old flame Robbie and is shocked to discover he has a suspected cancerous lump. Will his brush with mortality reunite them, or will Serena's feelings for Bernie scupper a happy ending?Ric is given an ultimatum by Tristan Wood - sign a proposal which will lead to the dismantling of Keller ward or face extinction himself. Is pragmatism the best policy, or will Ric take the moral high ground and face the consequences?