Fire and Water don't mix, or do they? (Leo Valdez x my character Kat fanfic)

Hi. I'm Kat. Kat Lilith. I'm adopted. My parents abandoned me as a baby. But once I go to camp half-blood, I find out things that make life clearer. I meet a boy. His name is Leo Valdez, and he's a son of Hephaestus. I'm a daughter of Poseidon. Fire and water don't mix, or do they?