Who Killed Coriolanus? is a sequel to Helen's Orphans. Both novels can be read on their own, but (spoiler alert) Who Killed Coriolanus? gives away the ending of Helen's Orphans.
Timon, who grows to adulthood in a Greek orphanage after the Trojan War, learns he's the sole surviving member of the Trojan royal family. He and his Greek companion Lukas receive an invitation to visit republican Rome, the city the Trojan survivors of the war have founded. Charmed by their prospective host's son Marco, they sail with him to Rome.
Their host, Marco's oddly protective father, is the military hero Coriolanus. Soon after his guests arrive, he involves them in his anti-republican schemes-which might include a civil war.