The Insider.com

When we last saw Dexter (played by Michael C. Hall) at the end of season 6, he was caught red-handed by his sister Debra (Jennifer Carpenter) -- who finally acknowledged her romantic feelings for her (adopted) brother -- as he ended the life of the Doomsday Killer (Colin Hanks).

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Related: 'Dexter' Fans Will Have Their Worlds Rocked

The cliffhanger ending raised the big question we were all waiting for: What would Debra do if she discovered that her brother was a serial killer, responsible for many of the homicides she'd personally investigated?

Now, "the moment of truth" is teased in this new promo for season 7 of the killer Showtime series, when some serious secrets may finally be revealed…

"Everything in my life has brought me to this point," says Dexter. "It's what I am. It's all I am. I can accept that. But can she?"

Will Debra come to terms with Dexter's "dark passenger" and allow him to kill again, arguably for good? Will her own personal code as a cop force her to betray the brother she loves (a little more than she should)?

Related: Brea Grant: 'Dexter' Lets Me Be Sexy

Tune in to Dexter when it returns September 30th on Showtime, and brace yourself…