Everyone’s learning Katherine’s secret in this week’s episode of The Vampire Diaries — including a “starving, bloodthirsty, vampire-feeding Ripper” Damon. What is his reaction to the news that it was Katherine (not Elena) who broke up with him, acting as a catalyst to his recent murder spree? Check it out in this sneak peek for Season 5, Episode 15 (“Gone Girl”).

“She’s brilliant,” a still chained-in-the-dungeon Damon says to Stefan, after his baby brother has delivered the awkward news.

Stefan is not impressed with his reaction: “We haven’t noticed that Katherine’s been inhabiting Elena’s body for weeks, and that’s all you have to say.” Damon maintains his nonchalance, so Stefan spells it out for him (and us): “And you realize it was Katherine that broke up with you. It wasn’t Elena … So, your little murder spree with Enzo where you killed Aaron; you nearly killed Jeremy; you tried to kill Wes, but you got infected with that Ripper virus. That was all you reacting to Katherine.” Do we detect a hint of smugness in Stefan’s delivery?

Damon might be picking up on the same thing. He tells Stefan: “I’m trying to figure out why you decided to tell a starving, bloodthirsty, vampire-feeding Ripper that his nemesis is still walking around alive and well while I’m stuck in this cell and can’t do anything about it.”

“I have it under control,” Stefan awesomely tells him. Which, on TVD, is usually foreshadowing for: things are about to quickly spiral out of control. Damon knows this short-hand, too...

“I’d love to hear this,” he skeptically tells Stefan at the end of the clip.

Do you think Damon is freaking out on the inside? Does Stefan really have it under control? Sound off in the comments below!

Catch the next episode of The Vampire Diaries on Thursday, March 6 at 8 p.m. ET on the CW.

Kayti Burt is a contributing writer for Wetpaint Entertainment with a penchant for all things pop culture. Follow her on Twitter and Google+!