A seashell, a rainbow, and a cat hat

What happens when 3 orphan friends find out they're demigods? Trouble. For 11 year old Ellie, a family was something out of her reach. That is until she meets her big brother, Percy Jackson and finds out she is a daughter of Poseidon. Now, she and her friends, a daughter of Iris and a daughter of Hades must travel cross country in search of a magic item. Will these rookies survive?