Once Upon a Marigold by Jean Ferris

Christian is gaga for Princess Marigold. But he's just a commoner, and no match for royalty. Heck, he lives in a cave with a troll! And now he's discovered another reason to put his love-soggy heart on ice: Queen Olympia is scheming to take over the kingdom--and she'll bump off her own daughter to do it. Can Christian foil her diabolical plans?