Sands of Kada

"Sands of Kada" is the eighth episode in the ninth season of Doctor Who, where the Doctor and Billy are joined by Captain Jack Harkness as they fight off an old enemy of the Time Lord's on the desert planet of Kada.

Synopsis
"I'm back Doctor, and I'm as charming as ever!" - Captain Jack

After stopping in Cardiff to recharge the TARDIS, the Doctor is once again reunited with Captain Jack, who comments that he looks more charming every time he sees him. He also says that he is surprised Billy is not a woman, and the Doctor promptly tells him he is not coming in the TARDIS. But Jack coaxes his way into the TARDIS and the Doctor ruefully agrees, setting it off for ancient Egypt. However the TARDIS suffers a time warp and crash lands on the desert planet of Kada, where no civilization has existed for over 2,000 years. The time travellers soon discover a science team led by Doctor Cadari Eventa, who are excavating the long since decayed High Temple of Kada. They unwittingly awake a dark presence on the planet, trapped by the Kadians centuries earlier. As the Fallen Idol begins to possess members of Cadari’s team, the Doctor and his companions are trapped when the temple collapses. Meanwhile the Idol begins to resurrect its Army of Sand, a vast horde of living statues buried in Kada with the Idol. The Doctor soon realises that the Idol is a great enemy of the Time Lords, called Haru’khahn and is faced with the decision to flee Kada or stop Haru’khahn and save Eventa and her team. As the Army descends upon the excavation site, Doctor Eventa finds a disrupt beacon built by the Kadians, which renders the Army temporarily immobile. Fleeing with the survivors of her team, she rendezvous with the Doctor, Billy and Jack and devise a plan to stop Haru’khahn. Using Eventa as bait to lure the Idol so the Doctor can destroy him with a restored Kadian weapon, the plan goes wrong when Haru’khahn possesses Eventa and kills her. The Doctor runs to the weapon and fires the beam into Eventa’s dying body, killing Haru’khahn in the process. After leaving Kada, the TARDIS returns to Cardiff and Jack pleads with the Doctor to stay onboard, whereupon he concedes. The three time travellers leave Cardiff, with the resulting air from the TARDIS blowing forward an old Torchwood poster.