Rita Wainwright's love affair with Barry Sullivan is flamboyant enough to deserve a dramatic ending, so that when the pair of them vanish over a cliff one rainy night, leaving a farewell note for Rita's husband, no one doubts for a moment that it is a case of suicide – except for Doctor Luke, one of the few people who genuinely liked her. Sir Henry Merrivale – the fabulous 'H.M.' – is staying in the area, having his portrait painted as a Roman senator. Although confined to a bath-chair with an injured toe, this does not stop him getting about – occasionally in toga and laurels – and solving what is too much for the sharp-eyed doctor.