Khusrau Shah hatched a conspiracy against Mubarak Shah. Khusrau Khan was one of the favorite of Mubarak Shah. Khusrau Shah got him murdered in 1320 and himself ascended the throne.
Battle of Chausa was fought near Buxar. Humayun was badly defeated and Sher Khan adopted the title of Sher Shah. Humayun barely escaped with his life from the battle field.