Cordelia and Wesley discuss Angel's obsession with Darla while he is down in the basement, where he has remained for a worrisome amount of time. When Angel appears with an armload of clean clothes, Wes and Cordy are relieved to learn that their friend has been doing nothing more ominous than laundry. Their hope turns to distress when Gunn, under Angel's orders, charges into the Hyperion Hotel with news that he has located Darla at a seedy motel. Angel leaves with him to rescue Darla from falling (back) into the clutches of Wolfram & Hart. Meanwhile, Darla sits in her hotel room and hears a knock at her door. Before she can speak, the door opens, but it is not Angel. Lindsey has found her first.
Lindsey takes Darla back to his office under guard. They are joined by a strangely solicitous Holland Manners as Darla, in response to Lindsey's empty politeness, cynically asks whether she has a choice about being there, or even a choice to be in the world at all. She scorns Holland's philosophical answer and bluntly asks how the firm wants her to mess with Angel this time, and is shaken when Holland reveals that the syphilis that nearly killed her 400 years ago has been reactivated. Meanwhile, Angel and Gunn check out Darla's motel room, where Angel senses Darla was there not long before, and that she was afraid.
In France, 1765, Angelus and Darla are on the run from a relentless vampire hunter named Daniel Holtz. When they take refuge from the swiftly approaching day in a dilapidated barn, their pursuers shoot the first flaming arrow into a beam just beside Angelus' head. As Holtz and his mob close in on the burning barn, Angelus steels himself for a fight to the finish, but - unwilling to go out in a blaze of glory - Darla knocks Angelus out and rides away on their only horse. Over her shoulder, she calls to him that perhaps they'll meet in Vienna. Angelus furiously watches his soulless companion abandon him to his doom.
In a dingy L.A. dive, Darla finds an unimaginative dork of a vampire that she almost fails to manipulate into siring her. Upon hearing his opinion that the idea of creating a companion for himself is "just weird," Darla replies in exasperated disbelief, "Weird? It's mythic." Finally, Darla drags the hapless vamp into the alley out back, but before he can bite her, Angel stakes him. In response to his ire, Darla tells Angel she's only here because he refused to turn her himself. She reveals that she is terminally ill, with scant weeks left to live. Angel brings Darla to the Hyperion Hotel while he hunts for proof that her "illness" is another scam perpetrated by Wolfram & Hart.
Expecting a fight, Angel kicks Lindsey's door in and is nonplussed when the young lawyer quietly extends an invitation to enter. Angel learns that Lindsey didn't believe Darla's diagnosis either, and obtained not only a second opinion, but a third, and a tenth, and even had her examined by his own doctor. Eloquently, Lindsey also tries to convince Angel to sire Darla, but Angel is adamant in his belief that siring her is not the way to save her. Angel returns to the Hyperion, where Darla again begs him to make her undead before she dies. Understanding that Wolfram & Hart is using Darla's illness to set a trap for them both, but unable yet to see exactly what it entails or how to avoid it, Angel refuses again.
Angel brings her to Caritas, where Darla sings the heartbreaking blues for Lorne. Reluctantly, Lorne divulges one way he saw that Angel might save Darla; Angel hovers impatiently as Lorne writes an address on a slip of paper. When Angel and Darla arrive at the address, there seems to be nothing but an empty swimming pool. Angel explains that he is being tested and must literally "take the plunge", mounts the diving board and dives headfirst onto bare concrete. Instead of smashing his skull, Angel arrives in a stone room. A master of ceremonies - the dapper Valet - approaches Angel and says, "Well, you certainly have faith. Now we'll test your valor." Darla has magically arrived as well and, when Angel objects to her presence, the Valet explains that as the prize, she is also his "collateral." The contest is to the death, and unless Angel passes all three trials, Darla's life is instantly forfeit. The Valet teleports her to the "antechamber," a waiting area set up like a castle's banquet hall.
Taking Angel's coat, shirt, socks and shoes, the Valet cryptically answers his insistent queries. For the first trial, Angel will be unarmed against an armed opponent whom he must kill. When Angel presses for more detail, the Valet claims to have no idea what the remaining trials might entail, because no one has ever survived the first. With a final farewell, the Valet disappears to join Darla, leaving Angel to face a large demon armed with huge hooks on long, heavy chains. Angel dodges several swings of the chains before being hooked through the calf and dragged toward the leering demon. In the antechamber, the Valet checks his pocketwatch and notes that Angel has survived an unprecedented 17 seconds. Distraught, Darla demands to see what's happening and the Valet touches her forehead. Clearly able to feel what Angel feels, as well as to see what he sees, Darla flinches as she finds her champion currently enduring a succession of heavy punches and kicks. When the demon draws its sword for the killing blow, Angel unhooks himself and blocks the thrust with the demon's own chain. Escaping into a narrow corridor circling the challenge floor, Angel ambushes the demon, grabs its sword and slices it in two at the waist. Believing he's won, Angel shouts and furiously pounds on the portcullis blocking the exit. Turning at a noise behind him, he watches (as does a despairing Darla) the revived demon literally pull itself together and renew the attack. Avoiding the whirling chains, Angel retrieves the sword and chops the demon in half again, this time hooking its torso separately from its legs and chaining them to handy brackets on opposite sides of the room. The portcullis slowly lifts and Angel moves on to the second trial.
As the gate slams down directly behind him, Angel faces a dark corridor; above him, the stone ceiling slowly grinds open to show the late night sky. Both walls and floors are completely covered with crosses of all types and sizes, some huge and wooden, some inlaid in gold and silver, some carved and embossed in relief into the stone blocks. Knowing the sun will eventually rise overhead, Angel limps as fast as he can over the burning floor, stifling screams as his bare feet sizzle and smoke. When he reaches the door at the corridor's far end, it is solidly locked. Looking over his shoulder at the fountain he passed in the middle of the corridor, Angel bolts back and sees a key lying at its bottom. Still watching, Darla breathes, "Holy water," just before Angel plunges his arm into the font. Screaming in agony, Angel fishes the key from the furiously boiling water then stumbles back to the door and opens it with the costly key. In the antechamber, the Valet again consults his pocketwatch and meditatively says, "He's quite remarkable." With a faraway look on her face, Darla says, "Yes. He is."
As Angel cautiously enters the next torchlit room, manacles magically snake from the walls and attach themselves to his wrists and ankles. The Valet arrives, congratulating Angel on his prowess while a wall of spring-loaded wooden stakes materializes. Angel learns that the third trial requires his life in exchange for Darla's. Passing the first two trials has earned Angel the choice of whether or not to undergo the final ordeal. At this point, if he so wishes, Angel is free to leave. Upon learning that Darla would die instantly were he to forsake this last test, Angel unhesitatingly tells the Valet, "No deal." The Valet steps across to the safety of the doorway, then turns back and proceeds to wonder aloud if the world wouldn't be a better place having in it a heroic Angel rather than Darla. In his vulnerable state, Angel is unable to conceal his doubt and uncertainty, but is nevertheless determined that Darla live at any cost. Struggling for composure, Angel says, "Do it." The Valet fractionally nods, the stakes release with a rumbling rush, and Darla shrieks in anguish both personal and vicarious.
Suddenly she catches her balance, stops screaming and opens her eyes. Her champion, alive and fully clothed, struggles to stand upright before her. Hearing that by accepting death he has won the third trial, Angel brushes aside the Valet's apparently sincere kudos. "Pay up," he grates. When the Valet rests his fingertips on Darla's head, however, he discovers that she has already been restored to life by supernatural means and that he is unable to grant the boon Angel has won. When Angel protests that Darla has earned a second chance, the Valet replies, "She's living her second chance." With a glance, the Valet manifests a brightly lit stairway leading up, then disappears himself. Angel is filled with rage that despite everything he's done, Darla is still going to die and smashes up the antechamber in a blind fury.
In Darla's motel room, she perches on the edge of the bed, while Angel mopes in a chair by the window. When he begins to mutter that maybe he could bite her after all, Darla cries "No!" with reflexive alarm. Angel doesn't quite realize that their moral positions have reversed. Not ready yet to accept their mutual inability to change Darla's fate, he protests the apparent whimsy of The Powers That Be. In response, Darla tries to explain. Her new understanding of how deeply Angel cares for her, she avers, is truly enough for her. She has come to believe that perhaps she really is living her second chance. "To die?" Angel asks hoarsely. "Yes," Darla replies. "To die the way I was supposed to die in the first place." After a moment, Angel seems to grasp that his wrenching sacrifices have not been entirely in vain. At that moment, four black-clad commandos break down the door and immediately taser Angel nearly senseless. Following his assault team in, Lindsey brutally yanks Angel's head back. "How did you think this would end?" he hisses. Drusilla glides gracefully into the room, vamps and bites Darla, then completes the siring by drawing her own blood for Darla to drink in turn. Silent and immobile, Angel watches in agony as Darla's precious, newly-saved soul is lost forever.