Nina is an 8-year-old who created the Petz Club.[4] Oscar is a 7-and-a-half-year-old, and is the detective of the group.[5] Tim is a 7-year-old, and is the sportiest of the group.[6] Marlou is the Petz Club's dog.[7] Gilou is a vet who helps the Petz Club with their investigations.[8]