Gerry Lenz was an employer of Thomas Brewster. He wanted to know about companions of the Doctor and was introduced to Polly Wright and Alistair Gordon Lethbridge-Stewart. Polly first met him when she travelled to a doomed planet, the planet Cosmic Finance Central Five, with the Second Doctor, Ben Jackson and Jamie McCrimmon. He helped them escape from the G-Naught. He was a retrieval trader, a scrap dealer, and tried to sell the Doctor some souvenirs. He thought that the Doctor was Polly's uncle and offered her a job as his personal assistant. He later rescued them from the G-Naught.
He was impressed in getting the Brigadier and Polly to London. He put Brewster in charge of overseeing his collection. He started a deal with Jo Grant to stop the global warming, which Clifford Jones was delighted at. (AUDIO: The Three Companions)