I failed at saving the kingdom and escaped but I found an idiot and a sociopath and now we can save the world

Dante and Rex, a fire and water elemental were on vaction in a lake when a young woman stumbled upon them, collapsing and nearly dead. She says she's not from this world and that they're her only hope to get a powerful jewel before the prince of the kingdom takes it to destroy the world. Follow this trio as they travel through the lands, make allies and save the kingdom before all is ruined.