Mirror Lakes is an area in The Beaks, with clear lakes that you can see your reflection in. It almost always has perfect weather and plenty of prey. The Mirror Lakes are very dangerous, said to transfix young owls in an unusual trance, making them vain and unwilling to leave.
The Band is on a journey to find the Great Ga'Hoole Tree . They encounter a bobcat (whom they kill) and a dying owl, said to be harassed by forces even more evil than St. Aggie's. Afterwards, they stop by a deadly place called Mirror Lakes. Gylfie and Twilight admire their looks in the lakes first, and are the first to fall into the mesmerizing trance. Soren looks in the Lakes afterwards, and Gylfie accompanies him, stating that "that coal mark on his beak brings character." After a moment of pondering about his looks, Soren agrees, and therefore also slips into the Lakes' trance.
Mrs. Plithiver notices that ever since they arrived at the dangerous Mirror Lakes, the Band had never once talked about their journey to the Tree. Mrs. Plithiver realizes that they have been caught in the Mirror Lakes' trance, making them vain, obnoxious, and unwilling to leave. Mrs. Plithiver orders them all to leave. All of them object, except Digger. They do fly away from the Lakes, grudgingly, though, escaping the trance.
Eglantine has been having strange dreams about her mother, Marella, living in a fir tree at the Beaks. She visits the Beaks to see her "mother," and the Mirror Lakes are mentioned. The owl she thought was her mother actually turned out to be Nyra, the mate of Kludd, mother of Nyroc or Coryn, and leader of the Pure Ones.