Biggles first met Lowe when he heard about the break in from Mr Carson, a Hampstead estate agent. Knowing that he could not withold what he knew about the case, Biggles went down to Westwinds to meet Lowe. Lowe was unenthusiastic about the involvement of a Scotland Yard officer into his case but he soon warmed to Biggles when he realised that Biggles could not only identify the assailants but could supply the motive as well when he himself was puzzled by the apparent senselessness of the attack.
Biggles told Lowe about the background involving the Roths and how a gang of professional political assassins led by Ludwig Karkoff had been sent to Britain on their trail. It was Karkoff's men, Molsk and Rallensky who had attacked Mrs Smith in a case of mistaken identity as they thought the Roths were staying at Westwinds with Dr Bruno Jacobs. Happy to cooperate with Biggles, Lowe agreed to share with Biggles any developments of his investigations while Biggles promised to share anything new on his end. In particular, Biggles was keen of getting the gang arrested and therefore out of the way but only if the charges could be made to stick and if the Roths could be located. Otherwise the gang might simply escape into a foreign embassy and seek refuge and another gang would be sent after the Roths.
Towards the end of the book, by a coincidence or otherwise, the Roths turned up at Hampstead police headquarters hoping to get help in locating Dr Jacobs who had moved away from Westwinds. Lowe decided to place them under police protection under Biggles could take charge of them. In the mean time. he had managed to find an incriminating fingerprint on a door handle at Westwinds. Mrs Smith had also come to and told the police that she had seen her attackers and felt certain she could identify them. Knowing from Biggles that the gang stayed at the Cosmolite Hotel on Cromwell Road, Lowe moved in to arrest them. Molsk and Rallensky were picked up but Karkoff drew a gun and fought his way out, injuring a constable in the process.
Lowe suspected that Karkoff might be headed for Saxton Old Hall where two more of his gang were staking out the country residence of Dr Jacobs and followed him there in a police car. He arrived just in time to see Karkoff drive off in a car after resisting an attempt by Biggles to arrest him. Lowe gave chase but the pursuit was short. Karkoff's car appeared out of control, proabably because Biggles had hit a tyre. The gang leader crashed into a telegraph post which fell onto the roof of the car, trapping him inside. By the time Lowe managed to extricate him, he was already dead.