The Moya crew send Scorpius to the Peacekeeper Command Carrier that is now led by Braca, as Grayza has been confined to quarters. They strap a nuclear bomb to his chest, threatening that it will explode if the Command Carrier tries to follow Moya. Sikozu elects to go with Scorpius.

The Moya crew discover that the Scarrans have sent an attack vessel, commanded by Akhna's lover, to take over Earth in order to gain access to the bird-of-paradise flowers that they need, because John destroyed their mother plant on Katratzi in "We're So Screwed Part III: La Bomba". The Peacekeepers offer to hold off the Scarrans, if John—and by extension, Earth—will form an alliance with the Peacekeepers. John says no, and speeds to the wormhole to intercept the Scarrans and figure out a way to stop them.

Harvey then argues with John in John's mind, with both of them wearing fluffy pink and white rabbit suits. Harvey convinces John there's no way he can save Earth without the help of the Peacekeeprs, and he's about to concede and talk to them, when Chiana talks him out of it. He begins thinking, and each of the crew suggests to him a way to unblock his mind so he can come up with a plan. Ultimately, John formulates a way to collapse a wormhole, the downside of which is that he will have lost his route to Earth. And if he fails, he will be trapped on that side of the wormhole, on an Earth controlled by Scarrans. He decides to try, and Aeryn insists upon going with him—if he is trapped, she will be with him. He, Aeryn, and a temporarily disconnected Pilot take a shuttle to Earth's moon, where John makes an emotional farewell phone call to his father. Then, they successfully collapse the wormhole, and kill the Scarrans. While Moya waits on the other side, she is attacked by the Scarrans, and is damaged. When John, Aeryn, and Pilot rejoin them, they travel to an unknown water world where Moya can rest and repair.

John and Aeryn row out a short distance from Moya in a small boat, and each tells the other they have something to say. Aeryn goes first, telling John the embryo has been released from stasis and that the baby is indeed his. An ecstatic John then asks her to marry him, slips his mother's wedding ring on her finger, and she says yes. As they kiss passionately, a flying vessel suddenly appears, targets them and hits them with a ray that shatters them apart. They collapse into a shower of thousands of tiny crystalline pieces that fall down into a heap at the bottom of the boat and overboard into the ocean.

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Wikipedia