What happened to Brady on Pair of Kings?
When Brady overhears Mikayla and Candis talking about how
Mikayla will never date him since he is the king of the island, he
leaves the island to go back to Chicago to prove him worthy of
Mikayla. Boomer hears about this and tries to follow Brady but when
a storm hits Kinkow, sending people from other island to them, it
forces him to stay. When a ship crashes in Kinkow, they find
someone who has the Kinkow birthmark on their bellybutton which
means he is also the king of Kinkow. It reveals that the king is
Brady and Boomer's long lost triplet brother, Boz. Technically,
that is the first episode.
Mitchel Musso left Pair of Kings because he was arrested and and
charged of DUI (driving under influence so eventually Disney
channel/XD fired him, although he will still provide the voice of
Jeremy on the Disney cartoon Phineas and Ferb.