An earl with a problem.

Nicholas Masterson, Lord Sharpe, has a problem with potions. He won't drink them, he craves them, and they're getting weaker by the day. When his spymaster uncle requests that he travel from London to India to investigate, he reluctantly agrees and hops on an early morning train.

A woman with a plan.

Ida Quimby has set herself a goal: begin a new life as an elite perfumer, selling potion-based perfumes to the highest tier of London society. But when her good-for-nothing brother reneges on his promise to supply her with the magic serum for her potions, she takes matters into her own hands and sets out for India to confront him.

The journey of a lifetime.

A chance meeting on a train brings Nick and Ida together, starting them down a path of mystery and intrigue that could get them both killed. Or lead them to a love for all times.