Not one to let being banged up in Sick Bay stop her, Max has had a brilliant idea. But she needs Markham to execute it on her behalf. The subject of this cunning plan is Peterson, struggling with another bereavement and not doing very well. What's needed to get him through it is sympathy, sensitivity, tact and understanding.

Step forward Mr Markham, for whom sympathy, sensitivity, etc., are things that happen to other people.

Combine a fanatic from R&D, a head of Security with his own problems, a steam-pump, two historians who can't even be in the same room as each other, some fractious Protestants and a large body of very dirty water.

Told in Markham's own words, this is the story of an intervention – St Mary's style.