Andrew Irwin is the younger brother of 5 Seconds of Summer's drummer, Ashton Irwin. He has a rare medical condition that let's his body age, but keeps his mind at the same age for a very long time. So, in his mind, he's about seven years old, while, in reality, he's almost fifteen. His parents send him to go live with his brother at the 5SOS house. Although, the boys aren't exactly thrilled to have a mentally unstable child in their home... (Includes Cashton and Muke, plus some Lashton thoughts (: )