Still pinned beneath the bandit's carcass, Medea hallucinates her dead sons, Tisander and Alcimenes. Tisander's trying to free her ties, but Alcimenes reminds his younger brother Medea killed them to get back at their father, Jason. Medea whispers that she's sorry; she loved them. Lykos appears and warns Tisander away: "It's not her time." Tisander kisses his mother and Lykos leads both boys away. Medea stares at the wristlet with the spider on it Tisander left in her hand until it disappears -- but she realizes his ghost did untie her. She frees herself and wriggles out from under the corpse.
Oracle tells Minos to send men into the mountains after Hero -- into all the mountains. Minos says it's too big a job, and asks if maybe her vision is too ambiguous to act on. After all, before, she thought the vision said Aegeus was the destroyer king. Is she sure the Lexicon is a curse, not a blessing? And how do the gods expect them to change their destiny without help? Faced with the prospect of the world's end, Oracle again asks Gaia for an assist, and is shown a flash of Medea.
Medea limps to the doorway under the golden apple, and finds Ariadne's shawl. Inside, she hears Hero moaning from inside Pandora's tomb, and the lid opens to reveal Hero floating on the surface.
The scribe assigned to follow Medea isn't revealing anything; he's still high on Medea's valerian tea, and Minos' threats and Oracle's face-slaps aren't helping (though Minos seems kind of turned on by Oracle's interrogation techniques). The scribe finally remembers where he last saw Medea: with Daedalus.
The man himself is about to sneak out after the priest's fallen asleep when Minos and Oracle arrive, Minos to wonder why Daedalus always betrays him in exchange for all the comforts he's offered, Oracle to blackmail him with a goddess-of-truth reference into telling her what he discussed with Medea. Daedalus admits that the axis of the ancients may have a door to Hell at its center -- and that Hero decided to go there. Oracle demands to know where it is.
Medea revives Hero with a potion, and he immediately scrambles towards the water again, to save Ariadne. Medea tells him he'll never return if he breaks the water's surface -- which means Ariadne's gone. Why wasn't Hero sucked under? What is that water, exactly? Medea says the Ring must have protected him -- from the River Styx, which is the source of the water, or where it leads, or something. Medea tells him to help her close the tomb. Hero -- who, just a reminder, has been "in love with" Ariadne for all of half an hour -- tearfully protests that he can't just leave her. He's gazing longingly into the tomb when a fog boils up. "Run!" Medea yells, and they flee.
Minos' priest explains that Pandora's tomb is at the center of the wheel, and opening it is a terrible, horrible, no good, very bad call. But it's apparently too late to warn Hero et al., as Oracle spots the fog rolling down over Mt. Parnassus. On the mountain, Medea and Hero see the same fog, and hurry away as Medea tries to understand why Hero let Ariadne follow him. "I've killed the only woman I've ever loved," Hero says, ridiculously, but Medea stops dead: "You truly loved her?" "With all my heart," Hero cries. Well, except for when he hated her for like seven episodes, but whatever: it means he's sacrificed love to the gods, the first of three sacrifices he has to make to solve the Lexicon. The second is his heritage, but Medea doesn't have time to explain that before the fog catches up with them. She does note that, as an immortal, Hero could bring back Ariadne and his mother from the underworld.
They find the streets of Athens deserted, as well as the castle. The prison's still full, though, and that's where Hero has gone in search of his heritage. Medea is gently telling the Lykorpse how sorry she is when she sees Aegeus nearby. They bring him to his bedchamber and Medea gives him a potion; he's very weak, but the fog is only an hour or two away from the city. Aegeus finally gives Lykos credit for dying defending his father, but babbles uselessly about the first king's ashes scattered on the wind and his sword buried under him, but the first thing of course makes the second thing impossible. Aegeus passes out. Hero fumes.
The priest suggests a sacrifice to Poseidon, but Oracle says Poseidon won't interfere in his brother Hades' affairs. Daedalus wonders if this isn't just, you know, a regular old fog, and proposes a test.
Medea prays for guidance finding the heritage of Athens. It seems to us like killing Aegeus is probably a pretty good sacrifice of Hero's heritage, but the smoke on the altar forms the shape of the first king's sword. Aegeus is no help -- "no one knows where it is" -- and Medea deduces that the ashes/burial conundrum is a riddle. The first king, son of the virgin Athena, had his ashes scattered on the north wind, not to the winds. Hmm.
Daedalus throws a rock into the fog. It doesn't land. He hears Icarus calling to him, and heads hopefully into the fog as Medea brings Hero to the never-melting shrine of the north wind, Boreas, explaining that Athenians consider him part of the family, and snow is their…cousin or something? Hero assumes the sword is under the shrine, then, but Medea says the king died long before the shrine was built. Then the fog swallows them both…
…as Daedalus stumbles into Icarus, who asks if Daedalus brought his sandals. "The ground here is so cold." Daedalus is taking his own shoes off when Icarus asks if he's sure he wants to touch the ground, and vanishes a moment later.
Medea and Hero soon lose each other in the fog at the palace, though they appear to still be in the same hallway near Aegeus' bedroom. Aegeus has also disappeared. Ariadne manifests and asks Hero why he left her; nearby, Alcimenes guilt-trips Medea some more. Ariadne asks Hero to come back with her, before the fog lifts. He can't, he weeps. He'll find her soon. She and Alcimenes both inveigle the living to kiss them, to entrap them in the world of the dead. Hero and Medea each almost fall for it, and Hero settles down for a dangerous snuggle with Ariadne before she returns to the underworld.
The priest reports that many of the Minoans have gotten scared of the fog and deserted. Those remaining may mutiny against Minos; he should avoid rallying (or punishing) the troops until the fog settles. Minos unsheathes his sword anyway. Oracle tells him his dead father is waiting outside for him, and he drops the sword and drifts towards the door.
Daedalus comes upon Icarus staring wistfully at the sun. He misses it. It's so cold down below. Daedalus starts to lead him out of the fog, but that soon devolves into Icarus Eeyoring that he died trying to live up to his father's expectations. He's mollified somewhat by Daedalus having saved the feather Icarus gave him, the one that inspired the ill-fated wings, but he breaks it into pieces and wonders what good Daedalus' genius is if it's confined to Minos' whims. Daedalus wails that he'd trade his life for Icarus's. Icarus takes his hand and says that for once Daedalus will follow him.
Hero promises to put things right, but Ariadne doesn't need his word; she needs his touch. She straddles him and pants about having him inside her. At the last moment, he pushes her away; he can't Do It with her in his father's bed. Fortunately she vanishes.
For whatever reason, Hero and Medea, who's ranting at the missing Aegeus to stop hiding under the bed, both figure out at the same time that the sword is under or in the throne. Each rushes to the throne room, and tries to dislodge the heavy stone chair (at the same time, but they're not together thanks to the ghost fog). In his fog timeline, Hero moves it a few inches, reaches into the hole underneath, and pulls out an old sword. "Put it back," Aegeus spits. Hero explains the solution to the riddle (which makes no sense, so we won't bother repeating it), and Aegeus grouses that Hero's taken everything of his, and picks up a spear. Either Hero puts it back or Aegeus will. Unlikely, in our opinion, and sure enough, when they begin sparring, Aegeus promptly gets his weapon stuck in a load-bearing column and has to kick his way free. He manages to clock Hero in the knee, but Hero soon guts him.
The fog clears, and Medea spots them on the ground. She rushes over and tells Aegeus to stay still. He's a great king, she sobs. Aegeus responds to that BS by dying. Go figure. His body dematerializes, and the fog recedes, slamming the doors behind it -- but then a frost begins to cover the throne room. Hero and Medea shiver as Hero apologizes, but Medea's encouraging: Hero's now sacrificed his heritage, as he's meant to.
Icarus leads Daedalus to the doorway under the golden apple. They have much to look forward to; he's proud of Daedalus. But the fog begins to dissipate around them. Daedalus finds himself alone and runs into the tomb to reach in after Icarus, but the lid closes.
As the priest and Oracle deduce that the snow falling around Minos's tent is Boreas's doing, Hero yanks on the frozen doors of the throne room, in vain. If they can't find a way out, they'll freeze to death. Dun!