“Harmony” is episode fourteen of season four of Stargate: Atlantis.
Colonel Sheppard and Dr. McKay are asked by some trading allies to escort the youngest of three sisters, Harmony, to some ruins. The sisters are all princesses and Harmony is the one who has been chosen to be queen.
McKay and Harmony do not get along and the thirteen year old Harmony starts intimidating Rodney. What is first expected to be a simple journey becomes more dangerous after the discovery that a beast guards the ruins, and that there are Genii trying to kill the princess.
Despite the danger, this is a rather humorous episode – especially when Harmony decides Sheppard would make a good king.