A Fearless Heart by Elizabeth Cole

Can love grow on poisoned ground?

Gabriel Courtenay works tirelessly for the British Crown, part of the elite circle of spies known as the Zodiac. He is afraid of nothing, but his latest assignment may be his most deadly yet. A serial poisoner is taking down England’s most influential politicians and personalities one by one, leaving a grim message behind each time. Gabe puts the clues together to point the way to a mysterious estate with a shadowy owner no one ever sees: Calderwood.
Lady Arcadia has suffered tragedy after tragedy, leaving her a shell of herself. Worse, local rumors have driven most people away from Calderwood. All Arcadia wants is to study botany and chemistry and care for her vast gardens of rare plants, but when a suspiciously handsome new gardener shows up asking questions, she knows she can’t trust him.
When another death strikes too close to home, Arcadia has no choice but to accept the help Gabe offers. As they uproot the twisted trail of an assassin using Arcadia’s scientific advances for evil ends, the two grow ever more entwined. Can Arcadia overcome her greatest fears in time to stop the killer…or will someone she loves become the next victim?

The ninth novel in the Secrets of the Zodiac, a series that blends dramatic romance with suspense, set against the high stakes world of the Napoleonic Wars.