G. A. Henty 
In the Reign of Terror [EPUB ebook] 

Harry Sandwith, a Westminster boy, becomes a resident at the chateau of a French marquis, and after various adventures accompanies the family to Paris at the crisis of the Revolution. Imprisonment and death reduce their number, and the hero finds himself beset by perils with the three young daughters of the house in his charge . The stress of trial brings out in him all the best eng qualities of pluck and endurance, and after hair-breadth escapes they reach Nantes. There the girls are condemned to death in the coffin-ships Les Noyades, but are saved by the unfailing courage of their boy-protector.