Sunny relies on an unlikely person for help in defeating a foe; Bajie learns a shocking secret from his past.
In a flashback, Bajie -- dressed in Abbot garb at the Monastery -- addresses his Novice, Flea, who is locked in a trunk. Bajie uncovers a butterfly engraved leather sheath in her belongings, but the blade is missing. Suddenly Flea bursts out of the trunk, her eyes black from cutting herself with the blade to unleash her power. She grabs two swords and attacks Bajie, who manages to shut her down and bring her back to normal.
After the fight, Bajie finds a book in Flea's backpack -- it's the Azra book. Bajie says the book will stay between them and thinks "Mother Fate" brought them together. She introduces herself as Minerva and they shake hands.
In the present, at the Sanctuary, the Widow tells Sunny that her temporary alliance with Quinn was a "necessary evil" and suggests Sunny needs her help to go up against Quinn. Sunny asks the Widow to protect M.K., but informs her that M.K. now "bleeds like the rest of us." The Widow tells M.K. that the gift can be a burden and it's probably best that it's gone.
Outside the Sanctuary, Bajie dirties his face and inflicts bruises to appear like a battered runaway Cog. At the gates, he cries and claims he escaped from Baron Chau's slave pens to swear allegiance to the Widow. The guards let him in.
Tilda shows M.K. to his quarters at the Sanctuary. M.K hopes his power doesn't come back and admits he feels free now. He shows her the magazine cover of Azra that he found and asks her to come with him on his journey to find it. But Tilda tells him that she's met someone who makes her happy. Tilda tries to introduce him to Odessa, but Odessa rushes off.
Tilda follows Odessa, who knows about M.K.'s power. She recounts the story of how M.K. slaughtered a Cog shipment she was also a part of. Tilda tries to defend M.K., but Odessa doubts his dark side is truly gone and warns her to stay away.
At Quinn's bunker, Gabriel tries ice cream for the first time and Quinn tells him he's one of only two of his men who've ever tasted it. Quinn recognizes Gabriel's yearning for purpose and hands him a duffel bag for a special mission.
Quinn spots Veil and notes she's been quiet since hearing about Sunny, but Veil refuses to "waste my words on a dead man." Quinn swears he's her husband forever and forces a kiss. Veil slaps him hard and Quinn returns the slap, then taunts her for being "drawn to men of violence." He has her sent to the ventilation room and whispers to Henry about the possibility of Henry growing up without his mother.
Waldo sees Sunny and notes he's back from the dead only to find "a new way to die." Sunny defends his mission to save his family and says it's his emotions that have kept him alive thus far. Waldo slyly advises Sunny to rely on his own training instead of trusting the Widow, then offers for Sunny to stop by Waldo's old Clipper shed for supplies. Waldo calls it a "farewell gift."
Quinn accuses Lydia of conspiring with Veil to kill him. Lydia plays innocent and overhears Quinn tell one of his men to lock down the bunker and "proceed with the final step."
M.K. watches Tilda train a Butterfly. He offers a wave, but she doesn't return it. The Widow tells M.K. his return has been a welcome surprise and insists her intentions for him have always been pure. She mentions ways to reactivate both her and M.K.'s powers and unveils the Azra book, but M.K. refuses. The Widow asks him to consider her proposal.
A truck of refugees arrives at the Sanctuary. Gabriel is among them.
Sunny prepares to head out with the Widow, but first asks her what happens after Quinn is dead. She assures they can simply go their separate ways, but Sunny expresses doubt. Gabriel is heard yelling, demanding to see the Widow.
Outside, Gabriel slits a Butterfly's throat and brings a message "from Veil" to Sunny that Veil is married to Quinn and baby Henry recognizes Quinn as his father. He warns Sunny that he will march to his own death and tells him how the Widow's the one who traded Veil to Quinn. The Widow throws a butterfly star at Gabriel right before he opens his coat and reveals explosives. Gabriel blows himself up, sending everyone around him flying. Sunny locks eyes with the Widow, who throws a butterfly star that grazes his cheek. He runs off and takes out a group of guards along the way.
Bajie appears, and he and Sunny hug. Sunny tells Bajie to find M.K. while he goes after Quinn. They plan to meet at the Fort when it's all over.
Wounded guards and Butterflies receive medical attention. Bajie spots M.K. and speaks to him in private about Sunny's mission. M.K. immediately wants to help, but Bajie relays the plan to meet at the Fort and adds that Sunny wants them to steal the Azra book. M.K. knows where the book is and mentions the Widow's plan to use it to get their powers back. Bajie says she's the "same old Flea," and M.K. realizes Bajie trained the Widow. Without the compass, M.K. thinks the book is useless, but Bajie comes clean about taking the compass from the Master's chambers and echoes his words to Flea about "Mother Fate" bringing them together. Odessa secretly listens to the conversation.
Quinn tries to comfort Henry, and Lydia insists he needs his mother. Quinn hands Henry to Lydia to be escorted to Veil, then takes a pull off of his pipe.
M.K. and Bajie search for the Azra book, but it's missing. The Widow walks in after Odessa reported what she heard. She admonishes M.K. and warns that Bajie will abandon him just like he did to her. Bajie refuses to leave without the book, but a swarm of Butterflies outnumber him. The Widow recalls Bajie's promise to help her decipher the book and insists he do so.
On the way to the ventilation room, Lydia sees one of Quinn's men assembling bundles of explosives and fastening them to the tunnel's walls. She tells Veil that Quinn has rigged the entire bunker and is ready to kill everyone before he lets anyone take Henry. Lydia proposes they find their own way out instead of waiting for Sunny.
Tilda approaches the Widow with news that she couldn't find Sunny in the woods. The Widow casts doubts on Tilda's genuine attempt and notes her behavior has changed ever since Veil was at the Sanctuary. Tilda admits she no longer knows who the Widow is. "Power's changed you," Tilda says. Tilda admits she should have poisoned her when she had the chance. The Widow tears up and backhands Tilda hard, and Tilda retaliates with a kick.
The two go at it with full force until the Widow grabs two swords and tosses one to Tilda. They lock blades and fly at one another around the Conservatory. The Widow cuts Tilda and tries to call a draw, but Tilda keeps up and gut kicks the Widow as the two continue to spill blood. The Widow kicks Tilda down a flight of stairs and cuts down a glass chandelier so it lands on top of her. After Tilda tells the Widow to finish her off, the Widow hits her with a spinning back kick. Tilda crumples to the ground.