Take a deep breath. It’s the penultimate ever episode of this brilliant show – don’t miss the finale on Monday at 9.00pm – and it’s going to be emotional. Louis finally succumbs to his illness tonight and France is in political chaos. Much like post-Brexit Britain, an unlikely leader steps in, as it is Treville named in Louis’ will, not the Queen. While Grimaud and his fellow power-hungry villains close in on the palace, it’s up to Athos, Constance and Sylvie to hide the Dauphin somewhere safe. Aramis is furious to be kept in the dark, and as he worries for his son he forlornly asks, ‘What happened to one for all?’ A darkly gripping hour with lots of rewards for loyal fans.