Darkest Plight

"Darkest Plight" is the 21st episode of season 4 and the 99th of the overall. It aired on November 13th 2016.

Official Description
The Turtle team hunts for their Sensei, but soon realizes they are being hunted as well.

Characters

 * Leonardo
 * Donatello
 * Raphael
 * Michelangelo
 * April
 * Casey
 * Splinter
 * Karai
 * Super Shredder
 * Tiger Claw
 * Bebop
 * Rocksteady
 * The Rat King

Trivia

 * Last appearance of the Rat King
 * The Rat King was a hallucination/ghost in this episode
 * This episode officially confirms that Victor Falco perished following his defeat at Splinter's hands in Of Rats and Men.
 * Identically to City at War having loose connections to the comic arc, Splinter's plot in the episode loosely follows his own plot from the comic with some differences.
 * In City at War, Splinter injures his leg after returning to the silo in I, Monster whereas in this episode, Splinter's leg is injured following his aerial battle with Super Shredder.
 * Throughout the episode, Falco attempts to tempt Splinter into falling into his control yet again, abandoning his humanity forever. The comics had Rat King debating Splinter and giving him advice.
 * To get Splinter to abandon his current life, Falco tempts Splinter to eat a rodent for strength, which he refuses. On the other hand, Splinter did eat the rats in the comic arc for survival.
 * Both in the comics and in the episode, Rat King is confirmed dead. The episode has a rat found in Falco's skeleton eyes, the comics have Rat King's corpse with shriukens as a reference to his first appearance in Mirage.