|“|| Jennifer: "I need a guardian... And that's a role that can either be filled by the three parents I was forced to take, or by you."|
Derek: "I can't help you. I'm not even an Alpha anymore."
Jennifer: "All I need is for you to help me get Deucalion in the right place at the right time."
Derek: "You just killed three of them on your own. What do you need me for?"
Jennifer: "You haven't seen him at his strongest-- I have. And if he's got Scott with him, I don't stand a chance unless I have you. [...] I have the eclipse in my favor, but the moon's only gonna be in the Earth's umbral shadow for fifteen minutes. That's the extent of my window. There's no decision to struggle with-- help me kill him, and the others live. Just help me."
With Deaton's help and advice, Scott and his friends use an ancient and extremely dangerous ritual to help them both save the lives of the people they love and stop Jennifer from achieving her sinister goal.*
(*Note: No official synopsis was released by MTV, so the aforementioned synopsis is from IMDB)
Scott, Allison, and Stiles awaken and discover where the Nemeton is located. Jennifer kills Kali and badly wounds the twins. Allison, Isaac, and-- after suffering a head injury in a car accident-- Stiles locate the Nemeton and rescue the three parents. The lunar eclipse begins, and all the Werewolves become powerless. Jennifer gives Deucalion his sight back so he can see her true form and then tries to kill him, but is stopped by Derek. Jennifer attacks Derek, but the eclipse ends and the Werewolves' power returns. Scott defeats Jennifer and becomes a True Alpha. Deucalion slashes Jennifer's throat, apparently killing her. However, shortly afterward, Jennifer is revealed to be barely alive, having survived Deucalion's attack, but is confronted by Peter when she attempts to use the power of the Nemeton to heal herself. Jennifer realizes that he plans to take Scott's power so that he can be the Alpha again, and Peter becomes so offended that he retorts that he's always been the Alpha before he claws out her throat, killing her for good.
- Tyler Posey as Scott McCall
- Crystal Reed as Allison Argent
- Dylan O'Brien as Stiles Stilinski
- Tyler Hoechlin as Derek Hale
- Holland Roden as Lydia Martin
- JR Bourne as Chris Argent
- Melissa Ponzio as Melissa McCall
- Linden Ashby as Sheriff Stilinski
- Daniel Sharman as Isaac Lahey
- Seth Gilliam as Dr. Alan Deaton
- Gideon Emery as Deucalion
- Felisha Terrell as Kali
- Charlie Carver as Ethan
- Max Carver as Aiden
- Adelaide Kane as Cora Hale
- Haley Webb as Jennifer Blake
- Eaddy Mays as Victoria Argent
- Matthew Del Negro as Rafael McCall
- Keahu Kahuanui as Danny Mahealani
- The title is a play on words in reference to the lunar eclipse that occurred in this episode, combined with the word "ellipse," a reference to the fact that this episode is the midseason finale of Season 3.
- Though the episode aired on MTV on Monday, August 19, 2012, the episode was accidentally leaked to season-pass subscribers on iTunes on August 16, and despite the fact that the episode was taken down within a few hours, it was still up long enough to make it on many illegal file sharing websites. Fortunately, this did little to negatively affect the ratings, as it received 2.081 million viewers when it aired as scheduled.
- Kali - fatally stabbed through brain with glass; killed by Jennifer Blake
- Jennifer Blake - throat clawed open; killed by Peter Hale
- "The White Room"
- Beacon Hills Preserve
- Look-Out Point
- Root Cellar
- Beacon Hills Animal Clinic
- Exam Room
- Reception Area
- Derek's Loft
- Argent Apartment
- Chris' Office
- Abandoned Distillery
- McCall House
- Scott's Bedroom
- "Burn the Obedient" by Korn ft. Noisia
- Jennifer viciously fights Kali in Derek's loft
- "Kids" by Mikky Ekko
- Closing montage: Scott talks to Deaton about his new "heart of darkness" while the McCall Pack is seen at school together; Derek and Cora leave Beacon Hills; Rafael knocks on Scott's bedroom door and gets it slammed in his face for his troubles; Peter claws out Jennifer's throat.