"'We Must Remember This'" is the 740th episode of Holby City and the 5th episode of the 17th series.
Fleur and Michael are pitted against each other in a race to diagnose a patient who is constantly arresting. When Fleur's ex-girlfriend arrives on Keller, it throws Fleur off kilter.
Mo and Jesse perform a high-stakes double lung transplant on a young patient. When there's a problem with the anaesthesia, the duo work together to solve the problem.
Serena is struggling with the deterioration in her mother's condition, particularly as Adrienne no longer recognises her. A war veteran helps bring them together.