Once Upon a Time Season 2 recently introduced an interesting new spin on its heart-related mythology. People with the right powers have always been able to physically removed hearts, but on Season 2, Episode 17: "Welcome to Storybrooke" Snow White (Ginnifer Goodwin) learned that certain acts can physically turn hearts black. This immediately raised some questions, such as, "If doing evil turns your heart black, why was Cora's (Barbara Hershey) a perfectly normal color?"

If you've somehow forgotten in the last few weeks, we got a look at Cora's heart on Season 2, Episode 16: "The Miller's Daughter," when Snow took it out of its box, cursed it, and then tricked Regina (Lana Parrilla) into putting it back into Cora's body, killing her. That act of manipulation and murder (which, let's be real, was pretty justifiable as self defense) was enough to add a dark mark to Snow's heart, but when we saw Cora's it was plain ol' glowy red. And if anyone's heart should be dark, it's Cora's.

So, what gives? Showrunner Adam Horowitz explained the incongruity on Twitter.

"[Cora's heart] wasn't inside her when she did bad stuff," Adam tweeted. "Remained pure in stasis."

That's a theory a lot of fans had already come up with, so it's nice to see it confirmed. Though it also has some interesting implications. For instance, it would imply that only wrong action, and not wrong thought will blacken a heart, since Cora had plenty of evil on her mind before she ripped her heart out.

Do you like this explanation? Share your thoughts in the comments below!

Catch the next episode of Once Upon a Time on Sunday, April 21 at 8 p.m. ET/PT on ABC.

Source: @AdamHorowitzLA

Rebecca Martin is an editor at Wetpaint Entertainment. Follow her on Twitter @BeccaDMartin.