In a remote cabin in the Swiss Alps, Adalind is in the throes of labor. The baby is coming tonight, whether she likes it or not. After a violent birth, her child arrives and Adalind feels her Hexenbiest powers coursing through her veins once again. The baby is healthy and clearly already demonstrating extraordinary powers.
Meanwhile in Portland, a Filipino couple is preparing to turn in for the night. Dana is extremely pregnant, and Sam heads to the pharmacy to pick up some prenatal medication for his loving wife. Dana falls asleep moments later, but her slumber is disturbed when a monstrous Wesen climbs a tree outside her bedroom window and protrudes its long, snake-like tongue into the room. The tongue slowly creeps across the floor, then jams into Dana's pregnant belly. The vicious beast enters the room and scuttles across the ceiling, jamming its forked tongue into Dana's stomach again. It's after her baby!
A concerned neighbor hears Dana's screams and comes to her rescue, scaring away the Aswang. The neighbor calls 911, and Wu intercepts the call. He recognizes the address; Dana is an old childhood friend. He speeds to the scene to find Dana drenched in blood and barely conscious. Before she passes out, she whispers one word to Wu: "Aswang."
As Dana is rushed to the hospital, Nick and Hank arrive at the scene to investigate. Nick immediately notices some peculiar claw marks on the window and tree outside. He immediately suspects a Wesen attacker, but he's never seen claw marks like this before. Meanwhile, Wu is devising a theory of his own.
Nick and Hank check in on Dana, who is recovering at the hospital. She and her baby are okay, but the doctor explains that the attacker attempted to suck the amniotic fluid from her womb. After checking Sam's alibi, Wu explains that he's known Dana since the two of them were babies. He wants to stay close to the investigation, which means that Nick and Hank will have to keep their Wesen suspicions a secret.
That night, Wu has a bizarre dream recalling his grandmother telling stories of a mythical Filipino monster called "Aswang," who drugs pregnant mothers and then eats their fetuses. It's the same word that Dana whispered immediately after the attack, but Aswang is just a myth... right? Wu isn't so sure anymore.
Back at the hospital, Dana doesn't remember much about the attack, probably due to the large quantity of Valerian Root sedative the doctors found in her system. Nick and Hank don't have any leads yet, but the Valerian Root fits with Wu's Aswang suspicions. It's a crazy idea, though. How could a mythical Filipino monster attack a woman in Portland? Wu decides to keep the theory to himself for now.
On a phone call with his brother in the Philippines, Dana's husband Sam reveals himself as an Aswang. He also seems concerned that his mother is in town from the motherland. When Wu stops by the house to investigate the scene of the crime, Sam abruptly dismisses Wu, raising his suspicion that Sam is somehow involved in Dana's attack.
Sam immediately heads to a local hotel to confront his mother, who is also an Aswang. She explains that it is Aswang tradition for the eldest son to sacrifice his firstborn child so that his mother can absorb the baby's life energy. If the ritual is not carried out, Sam's mother will be dead within a month. Sam refuses to help his mother, but that won't stop her from eating Dana's baby.
Wu knows that Sam is somehow involved in Dana's attack, but so far all the evidence points to the ridiculous theory that a mythical creature attacked her in the middle of the night. In the trailer, Nick discovers a journal entry that helps him to confirm the attacker as an Aswang Wesen. The detectives know that Wu is close to the case, and Hank wants to enlighten Wu about the hidden Wesen world. Nick refuses, though. It's just too much revelation to drop on a person all at once.
At the station, Wu struggles to explain his Aswang theory to Nick and Hank. Wu thinks that Sam might be plotting to kill his pregnant wife and make it look like a supernatural occurrence. He admits that the idea sounds crazy, and Nick and Hank summon all of their willpower to play dumb to Wu's theory.
Later that night, Wu stakes out Dana's house and witnesses Sam's mother transforming into an Aswang and climbing the tree outside Dana's bedroom window. He can't believe his eyes. Is this real?! Searching for Sam's mother, Nick and Hank head to her hotel and discover a jar of Valerian Root in her luggage. In a flash, they're off to Dana's house.
Sam's mother knocks her son unconscious and attacks Dana in her room. Wu bursts through the door just in time to find Sam's mother in her Wesen form. He can't believe his eyes, and the Aswang attacks him before he has time to process the situation. Just before the Aswang kills Wu, Nick arrives and shoots the Aswang dead. Unable to process what he's just seen, Wu's mind snaps.
The next day, Wu checks himself into the psych ward. Nick and Hank drop by for a visit, but Nick still refuses to tell Wu the truth about the Wesen world.