Billy and Mandy are a mismatched pair of youngsters who befriend the Grim Reaper after winning a limbo contest against him. Since the Grim Reaper lost, he has to be their friend, and the three go on adventures together. Between school, family and visitors from the spirit world, Billy and Mandy sometimes need help to clean up the messes they get themselves into, and that's where Hos Delgado comes in. Hos and the Grim Reaper are not friends, and with Mandy's bossy nature and Billy's curious attitude funny escapades ensue.