Doctor Who/Recap/2007 TDWAS the Infinite Quest

Hey, we haven't had a good Gotta Catch Em All serial in a while, have we? Must be time to hunt the wild Plot Coupon.

Guy named Baltazar wants to conquer Earth; Doctor and Martha thwart his plans and send him to the icy prison planet Volag-Noc; guy swears vengeance; same ol' same ol'.

Some years later. Martha is surprised to run into Baltazar's pet mechanical bird, Caw, whom they had freed when they sent Baltazar packing. Caw remembers Martha, thanks her for his freedom, and gives her a little metal brooch... and a quest.

Baltazar, says Caw, has escaped from Volag-Noc and is searching for The Infinite, a legendary old spaceship that grants its finder his or her heart's desire. Given that Baltazar's heart's desire is unlikely to make the universe a cheerier place, the Doctor and Martha had better find it first. Caw gives them a datachip, which has the location of the next datachip, etc., all the way to the last datachip, which has the location of The Infinite.

First stop: an oil rig on an unpleasant-looking planet. The rig is being robbed by Sky Pirates, so three guesses where our heroes end up. Captain Kaliko thinks that the Doctor and Martha are spies from the oil company, and is all ready to make them Walk the Plank when the real spy—her first mate—reveals himself. Big Damn Villains ensues. The pirate ship is broken up; Kaliko escapes in an escape-pod-thingy, but turns up dead next to the TARDIS. Still wearing her datachip-shaped pendant, fortunately.

Next up is the planet of the lizard people. Well, planet of the lizard person: Mergass, a war consultant; and his clients, a hive of giant alien aphids. Mergass also has datachip-shaped jewelry, so the Doctor and Martha stick close to him while he strategizes with the hive queen about their war against... humans, who also live on the planet. And who, it turns out, were there first, and were attacked by the aphids, and are the good guys for a change. The Doctor brings about peace by posing as a pirate leader, in a bit of over-the-top voice work from David Tennant that is either hilariously stupid or stupidly awesome, depending on one's taste for silly piratical accents.

Last datachip. Why, it's on the icy prison planet of Volag-Noc! What are the odds? The Doctor forgot his get-out-of-jail-free card, though, and finds that the galactic statute of limitations hasn't quite run out on some of his more notorious doings. His stay will be somewhat longer than planned.... unless, of course, he MacGyvers his way out.

Turns out Baltazar had played the Doctor for an Unwitting Pawn. He takes the final datachip, takes Martha hostage, and takes off for The Infinite. The Doctor catches up with them—though he later says it's been three years in his timeline—just in time to save Martha from the illusion of her heart's desire (a hologram of himself), but not able to save Baltazar from his (a hologram of piles o' treasure).

Tropes

 * Arson, Murder, and Jaywalking: The Doctor is incarcerated on over a thousand offenses, including planetary destruction and overdue library fines. He really should've returned those books.
 * Gotta Catch Em All
 * Derelict Graveyard: The Infinite
 * Informed Ability: The Doctor calls Baltazar "the greatest despot who ever, ever lived." Despite the fact that he seems to have no dominion over anything aside from his pirate ship and ends up getting defeated by (in order) a spoon and a robot parrot.
 * Ten likes to exaggerate, though.
 * Knight Templar: the prison governor
 * MacGuffin Delivery Service
 * Out of Time, Out of Mind: The Doctor
 * Penal Colony
 * Pirate Girl
 * Plot Coupon
 * Running Gag: The Doctor still thinks that, no, no, she shouldn't do that.
 * Sky Pirates
 * Talk Like a Pirate
 * Uncanny Valley: In an otherwise realistically-proportioned cartoon, some of the face angles had the eyes only-just-a-little-bit wrong.
 * Whole-Plot Reference: This is an animated rehash of The Keys of Marinus.