By the age of 28 he had become sufficiently well-established as a promising young barrister to take a month's holiday in Sussex, where he meets and becomes friendly with 19 year old Stella Derrick.

A few days later Thresk resolves to write to Stella to ask if she will join him, but before he can send the letter news arrives that the Resident has been found dead outside his tent, shot with his own rifle.

When it becomes clear that Stella has no real defence and is likely to be convicted, Thresk comes forward and gives perjured eye-witness evidence of an arm reaching beneath the tent.

When a local army captain, Dick Hazlewood, falls in love with her, his suspicious father enlists the help of a solicitor friend to establish her guilt.

He concocts a ruse to persuade Thresk to visit, with a view to confronting him unannounced with Stella and questioning him closely about the evidence he had given in court.

Thresk deals with the informal cross examination well enough to convince the solicitor of his veracity, but he privately insists to Stella that she must be absolutely honest with her lover and admit her guilt.

Thresk believes that she has agreed to marry Dick only to acquire respectability, and when at last she understands that his purpose in visiting the camp was to invite her to leave her husband she exclaims "If only I had known ... What a difference that would have made!