Mathias stays in Aber and takes over as CS.
It seems likely that Mathias is technically in charge of the place in the interim already, since as far as we know he's the most senior officer at the station. Also, he's got his budding romance with Manon to maintain. His only other option is to try to chase his estranged wife to Canada and he's got nothing now back in London to go back to.Oh, and maybe Rhys can finally be in charge of the team, too, like she was when Tom went AWOL after S1, and resented him being foisted back above her again.
Then again, from Tom's perspective being at the forefront of all of it, Aber and Ceredigion is turning out to be a really fucked up place.
