- You may be looking for the titular diamond or the unrelated Eye of Akasha.
Majorca, Spain: After a series of stressful adventures, Amy Pond and Rory Williams are dropped off by the Doctor on the island of Majorca in the Mediterranean Sea for a relaxing vacation. Unfortunately, the time they materialise in is less than ideal. Whilst waiting at the airport for a flight out, Amy complains that the hotel that looked so nice in the brochure isn't actually built yet, it rained the whole time, and the only "exotic food" available was soggy fish and chips at a fake English pub. Rory, whose dogged attempts at optimism are repeatedly stymied by Amy's complaints, finally manages to point out, "At least we'll be home soon, eh?" This turns out not to be true either, as an announcement immediately informs them that flights off the island are delayed indefinitely. Before Amy can finish threatening a dire fate for the people in charge, Lady Christina de Souza appears, striding confidently to the front of the queue, explaining that she has a private jet and a pressing engagement in Utah. Before Rory's open admiration of Christina and her jet can get him in too much trouble with Amy, the Doctor saves the day by materialising the TARDIS in the middle of the airport and offering the couple tickets to "the most luxurious star-liner in the galaxy." Delighted that her holiday might not be a total disaster, Amy accepts the tickets over Rory's assurances that all they wanted was to go home. After a brief altercation with the local police is settled with judicious use of the psychic paper, the three head off to the star-liner Excelsis, which is travelling through the Ashaya Nebula, "a couple of years" in the future and "a few galaxies over," according to the Doctor.
Captain Vorch of the star-liner Excelsis is introduced to Ambassador Trelayce of the Karkaptan Inheritance by his Ashayan first mate. The captain dismisses his first mate X.O.'s attempts and asks him to go see if anyone needs their drinks refreshed. "These Ashayans forget their place," Vorsh explains to the ambassador apologetically. Trelayce acknowledges that the sight of the dying red giant at the nebula's core is beautiful to look at, but suggests that the native Ashayans might not find it so lovely to see their world die along with their sun. Vorch rejects the notion that the Ashayans are trapped on their planet, noting that the Vodiran Bloc has offered them all positions as vassals and thralls. Lady Christina de Souza strides in then, having somehow made it off Earth and on to the star-liner before the TARDIS and its crew. She introduces herself to the captain and allows him to flirt shamelessly while her disgusted alien companion, a catlike creature she calls Neko, abandons her shoulder in order to mingle and cough up a hairball, not necessarily in that order.
Meanwhile, something is screwy with the TARDIS. As the Doctor tinkers with its controls, sparks fly from the console. The Doctor tells Amy and Rory to go ahead while he tries to fix things. Upon exiting the TARDIS the Ponds find themselves falling, realising the phone box is somehow parked at a ninety degree angle and perhaps a metre off the floor. The Doctor agrees that parking sideways was a bit odd.
The scene shifts back to Lady Christina and Captain Vorch. The captain is still flirting, but Lady Christina manages to get him to explain that the ship's shields are powered by the Eye of Ashaya, the largest diamond in the galaxy, plucked from the centre of the red giant the ship is approaching. In fact, it seems that the extraction process is responsible for causing the star to die and dooming the Ashayan homeworld. "The price we pay for progress," says Vorch. "So much easier when someone else pays," Lady Christina replies, a look of disdain on her face. The two walk by Amy and Rory, who are shocked to realise she is the same woman they had seen at the airport on Earth not long before. With Christina out of sight, the Doctor interrupts the Ponds to give them the quick version of the mysterious woman's backstory: she is a thief, billionaire, socialite, and bus driver who he had last seen on the run from U.N.I.T. Amy tells him they saw her in Majorca, where she had announced her intention of going to Utah. "Of course," says the Doctor to himself. "The Vault. Christina, you sly fox."
Meanwhile, Neko silently observes three Ashayans conspiring in a dark corridor. Two bald Ashayans urge X.O. to consider helping them with their plan, which the first mate describes as mutiny and terrorism. X.O. refuses to listen to any more of their plan, but declines to alert his superiors to their scheme. "Sooner or later, sir, you're going to have to pick a side," one of the conspirators warns him. "You either stand with the oppressors... or with the goddess." Neko runs back to Lady Christina's quarters, complaining that her perfume makes the room smell like "a Betelgeusian bordello." Neko warns Lady Christina that the Ashayan crew is plotting something; Christina says she will have to keep them occupied somehow, but before she can elaborate, Captain Vorch walks in. She shoots him in the face with a neural pacifier and informs him that they are going to set the controls of the ship for the heart of the sun.
Neko complains that the now-pacified captain is going to ruin their scheme with his obvious drooling. Christina dismisses her partner's concerns, saying he's already given her everything they need. She holds up the captain's headset, as if to demonstrate. Neko wishes Christina luck as she dons the headset, touches a spot near her ear, and in a puff of smoke seems to transform into Captain Vorch. Meanwhile, hidden behind a corner, Amy and Rory watch Christina transform. Amy mutters to her husband that this obvious skulduggery confirms her theory that Christina was up to nothing good.
Christina, disguised as Captain Vorch, surprises the Ashayan crew with a snap inspection. Assuring X.O. that he runs a tight ship, Christina surreptitiously inserts a data stick into a slot, a program in it overriding the ship's controls.
Amy is convinced that Christina intends to steal the diamond powering the ship. Rory suggests that Amy is only upset that Christina jumped ahead of her in the queue at the airport, but Amy claims to be motivated purely by moral outrage. What's more, she insists, Rory is as well. They go to find the Doctor, who is even now surprising Christina by waiting silently in her dark room. Christina claims the Doctor must have mistaken her for someone else, but the Doctor uses his sonic screwdriver's cancel-hologram setting to reveal her true face. Christina begrudgingly admits that she may not have been entirely who she seemed, but insists the Doctor could not possibly be the man she met. It takes only a quick mention of San Helios and flesh-eating Tritovores, however, to convince Christina that this is indeed the same man with a new face. Christina comments that she finds the Doctor's new appearance to be "distinguished, in a slightly squashed sort of way," but that she will only accept his bow tie if it's intended ironically. The Doctor smugly suggests that Christina must have gotten off world by stealing a ship from "the vault," an eccentric billionaire's collection of alien paraphernalia. By way of confirmation, Christina says she made it halfway across the galaxy since then (contradicting the Doctor's earlier statement that the Ashaya Nebula was a few galaxies away). The Doctor, suspecting the worst of Christina, asks her if she's been being good. "Where's the fun in that?" returns Christina, quite sensibly.
Amy, despite the grumblings of her sceptical husband, bangs frantically at the TARDIS doors, shouting for the Doctor. An Ashayan, alerted by all the noise she's making, comes to see what the problem is, and Amy tells him that someone is trying to steal the diamond. The Ashayan, who was plotting to steal the diamond himself, brandishes a stun ray and forces the Ponds into a service elevator. As they march, the Ashayan explains his people's backstory in great detail, including how the Vodirans plucked out the "eye of Goddess," causing their sun to sicken and condemning their race to death or enslavement. He mistakes Amy and Rory for Vodirans themselves, who resemble humans much more than his own squat, egg-shaped species. But the Ashayan's attempt to make the alleged Vodirans understand his people's plight through by beholding the glory of the goddess's eye directly is foiled when they find the diamond already missing. Oh, there it is: the Doctor's got it.
The Doctor intends to fix the TARDIS by using the diamond to sift the data of the Matrix, which has apparently survived the destruction of Gallifrey in some form. The Doctor disarms the Ashayan using his screwdriver's explode-stungun setting, but his plans to make use of the diamond are derailed when an alarm alerts everyone that they're (thanks to Christina's override) hurtling into the heart of the sun and (thanks to the Doctor stealing the diamond) the shields won't even work. While most of the passengers are escaping in life pods, Christina upbraids the Doctor for ruining her plan and nearly getting them all killed. It's only then that the Doctor realises Christina was there not to steal the diamond, but to return it to the star and save the Ashayan civilisation. Together they do that and clouds of hydrogen gas are drawn into the red giant, reigniting it. The Ashayans celebrate the fact that they have a home again and drive the Vodirans off their planet. Amy, listening to them, comments that home sounds pretty good. The Doctor, for his part, says that without the diamond he's going to have to put off fixing the TARDIS; the immediate priority is to get off the ship before he has to explain things to the crew. He invites Christina to come along with him, saying he might have misjudged her the first time they met. She answers that maybe something of the Doctor rubbed off on her, but rejects his offer. "I'm nobody's passenger," she says. "Be good."
- The Doctor mentions a time when the Graske infested a nunnery.
- Because Amy and Rory expect to get home by plane instead of the TARDIS, it seems likely that the comic begins in the Ponds' own era (the early 21st century). The technology and manner of dress of the locals support this.
- Amy comments on her exasperation with 19th century adventures, and the story opens in Majorca — both references to other IDW stories like Hypothetical Gentleman and Ripper's Curse.
- Betelgeuse is mentioned. (TV: Destiny of the Daleks)
- The Doctor says he last saw Lady Christina de Souza escaping a U.N.I.T. tactical squad. (TV: Planet of the Dead)
- The Doctor, Amy, and Rory were last in Utah during the Doctor's apparent death at Lake Silencio. (TV: The Impossible Astronaut, The Wedding of River Song)
- The Doctor says there used to be easier ways to rekindle a dying star, but you just can't lay your hands on a decent stellar manipulator these days. (TV: Remembrance of the Daleks)
- The Doctor says Christina got her alien tech from a vault owned by an eccentric billionaire in Utah. (TV: Dalek)