After a London Underground pest controller was attacked and poisoned in the Underground and admitted to hospital, he was placed under Dr. Lewis' care, who was confused and awestruck at how the pest controller was dying from venom and believed that he had been assaulted in the Underground. When Nick Cutter and Claudia Brown came to the hospital to investigate the attack on the pest controller, Dr. Lewis explained what she knew about the attack and what was happening to the pest controller.
Later the same day, when Stephen Hart was admitted to the hospital bitten and poisoned by an Arthropleura as the pest controller had been, Dr. Lewis and her staff attempted to care for him and keep his condition stable as long as they could. Dr. Lewis believed that Stephen had no chance of surviving unless the hospital could get a sample of the Arthropleura's venom in its pure form to locate an anti-venom, and instructed Abby to do that.
The Home Office later obtained a pure venom sample from the Arthropleura and sent it to the hospital, where it was used to locate an anti-venom for Stephen and successfully help him survive and recover from the Arthropleura bite.
Dr. Lewis was shown to be strong, stern and determined about helping and saving her patients.