Set on a train from Glasgow to London, a government agency intervenes in escalating events onboard. Two strangers work together to save passengers as the train hurtles towards disaster.

Low-born Helena is convinced that she and the high-born Bertram are meant to be. Bertram does not, so he runs off to fight in the Italian wars with his "#bff" Parolles, where he meets Diana. The lopsided love triangle all comes crashing down when the two women meet and devise a diabolical plan.