Possivelmente "Os Doomfarers de Coramonde"de Brian Daley? Algumas das pistas confirmam, mas faz tanto tempo desde que eu a li que não me lembro de muitos detalhes.
Just yesterday, Sergeant Gil MacDonald and his APC crew had been fending off an ambush in a Viet Nam jungle. In the middle of the firefight, some kind of magic spell had transported them to this Fantasy Land complete with flying dragons, wizards, crazy castles, and dispossessed princes. They would stay trapped here forever unless they could rescue the sorceress Gabrielle. Master magician, Amon, held her captive in his palace; and to reach her, Gil and his men would have to infiltrate Hell itself.
Livros do Google forneceu os detalhes de que sim, ele nomeou seu cavalo Jeb Stuart. Estou chamando!
Gil was enticed into jumping Jeb Stuart through a flaming hoop,
Houve uma sequência chamada "Starfollowers of Coramonde", que eu nunca li.