Spring 1915. Secret service spy Jack McColl is in India, defending the empire against Bengali terrorists and their German allies. In England, meanwhile, journalist Caitlin Hanley is rebuilding her life after the execution of her brother - an IRA sympathiser whose terrorist plot was foiled by Caitlin's ex-lover, the very same Jack McColl.
The First World War is giving fresh impulse to those causes - feminism, socialism and Irish independence - which she has long supported. But the threat of a rising in Dublin alarms McColl's bosses as much as it dazzles Caitlin. If another Irish plot brings them back together, will it be as enemies or lovers?