[Warning: The following contains spoilers from Thursday's episode of How to Get Away with Murder. Read at your own risk!]

We knew the final season of How to Get Away with Murder would give us a few last twists and turns, but we never thought it would get this insane! In addition to confirming our speculation about Hannah (Marcia Gay Harden) and Sam's (Tom Verica) childhood incest, How to Get Away with Murder also revealed that they had a child together when they were teenagers.

After Vivian's (Marsha Stephanie Blake) shocking accusation that Hannah and Sam had been lovers, Annalise (Viola Davis) starting digging for evidence. At first, nothing seemed amiss, even though Annalise and Bonnie (Liza Weil) admitted the whole thing made a lot of sense. Sam treated both of them for childhood trauma having to do with being sexually abused by their own family members, and this kind of secret would have perfectly explained why he was so adept at understanding and sympathizing with their stories. If he had been a victim, himself, with his older sister as his abuser in his parents' absence, it would make sense that he'd know exactly what to say during therapy sessions with other victims.

The final shred of proof they needed came when Annalise discovered that Hannah missed nearly three months of school during her senior year for a suspicious illness. Realizing this illness might have been code for a pregnancy, she deduced a logical delivery date and started hunting for this secret incest love child. And she didn't have to look very far...

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Who else happened to be the exact right age and had a birthday in the final week of Hanah's absence? Frank Delfino (Charlie Weber).

Remember way back to those flashbacks about Sam getting Frank out of jail? He explained his willingness to help was because Hannah knew Frank's aunt in high school and called in a favor. Frank has been tied to Hannah since the very beginning! Annalise obviously had the DNA tested, and sure enough, Frank's DNA matched. He is officially the son of Hannah and Sam Keating.

It's probably safe to assume that Frank never knew — though the burden of that knowledge could explain some of his more violent tendencies — but the big question here is whether Sam knew who he was. He treated Frank terribly over the years, even coercing him into killing Lila Stangard (Megan West) back in Season 1. Can you imagine ordering your own son to kill your pregnant mistress so she doesn't have your other secret love child? This show is so bonkers!

Now, all that's left to do is wait to see whether Bonnie and Annalise reveal this discovery to Frank and what kind of gasket he blows when and if they do. Those fireworks are going to be something to see, for sure.

How to Get Away with Murder airs Thursdays at 10/9c on ABC.

Charlie Weber,<em> How to Get Away with Murder</em>Charlie Weber, How to Get Away with Murder