Having failed to restart his relationship with Louisa Glasson, Martin is forced out of the picture with the arrival of her dad, Terry Glasson. Terry has hatched a scheme with a colleague, Jonathan Crozier, to smuggle in some explosives which they want to use to help them in a robbery. Terry decides to back out of the smuggling, and things get even worse for Doc Martin. As he finds himself held hostage, along with Louisa, by a paranoid Jonathan, as he attempts to force Terry to carry out their plan.