An Unusual Botanist (A Nest of Spies) (A Nest of Spies #3)
Janis Linford

When Isabel Oakley’s father sends her to stay with a viscount’s family in London, he wants her to find a husband. She'd prefer to complete her botanical dissertation and submit it to the Royal Society for the Copley Award. But when she’s drawn into helping Ashley, the viscount’s son, the award is the last thing on her mind...
Ashley Newcott, a betrothed spy and cipher expert, undertakes a mission to decode five mysterious letters. But they’re unlike anything he’s seen before. Desperate to uncover their contents before his wedding to a belle of the season, he asks Isabel for help. As the plot becomes known, they’re both plunged into increasing danger that threatens to change their hearts and lives forever.