Wilf makes his way through Christmas Shoppers , but is drawn to a church. Inside, as a choir sings, he is forewarned by a mysterious woman ...

The Doctor arrives on the Oodsphere , and is taken by Ood Sigma to see the Ood Council . Here, he discovers the bad dream of the Ood and everyone in the universe - the Master! As more visions are revealed the Doctor realises he must get back to Earth. However, even as he does so, Lucy Saxon is taken to a chamber and the Master is resurrected by his devout followers. As Lucy tries to thwart his return, the prison explodes ...

The Doctor arrives to find the prison debris and decides to track down the Master, unaware that Joshua Naismith and his daughter are similarly searching . Meanwhile, Wilf leaves home and is picked up by his fellow members of "The Silver Cloak" . As they drive through the streets Wilf explains how they must search for the Doctor.

The Master has tried to disguise himself, but being 'hungry' kills those who recognise him . The Doctor soon finds him, and then gives chase , but loses track as Wilf and his group find him. They are dropped off at a cafe and Wilf explains his fears, then points out Donna and her fiance Shaun. The Doctor explains the Master, then heads off leaving Wilf alone .

Tracking down the Master the Doctor confronts him but the Master drains energy from him . They discuss the Master's hunger and the sound of drums, which the Doctor discovers is tangible. However, as he tries to convince the Master he can help him a squad 'kidnap' the Master and knock the Doctor out.

Christmas Day at the Noble household , and Wilf again sees the mysterious woman who tells him to bear arms. As he digs out his old service revolver, Wilf sees the Doctor out of the window and goes out to meet him. As Sylvia confronts them they leave in the TARDIS .

Joshua Naismith has the Master, and wants him to assist in getting his 'Gate' working . Using Wilf's Naismith book as a clue, the Doctor and Wilf arrive and make their way into the mansion . There they meet up with the Vinvocci 'Rossiter' and 'Addams' in the basement who are here to get the Gate back - in reality it is planetary healing device. The Doctor realises what the Master is up to in helping Naismith and rushes to stop him - too late, as the Master leaps into the Gate and uses it to turn everyone on Earth into himself, including the President at the White House and people on an estate . As Donna watches her mum and Shaun change too , the Master is victorious!

Meanwhile, at the end of the Time War the Time Lords discuss how to survive . They realise the Master could be the key to their salvation ... Back on Earth, the Master has Wilf and the Doctor tied up and gloats as his various selves report in . Suddenly Wilf's phone rings - it is Donna who's scared of what's happening. As the Master's selves try to capture her, she releases the building energy in her head and knocks them all out, including herself . As the Master tries to find the Doctor's TARDIS he is knocked out and they all escape , eventually beaming out of the basement to avoid recapture.

The Master's UNIT versions attempt to track the Vinvocci ship but the Doctor has cut all power to make it invisible. With all the drumbeats available, the Masters attempt to track where it eminates from - leading to Gallifrey, where the Lord President sends back a white point star diamond to boost the Master's machine .

On the ship, Wilf is again visited by the woman, who tells him to give his gun to the Doctor . As the Doctor realises the Master intends to bring back the Time Lords he reactivates and flies the ship to the mansion , then drops in from above. Inside, he discovers the Time Lords are back, who then return humans to normal and announce Gallifrey is returning - this is witnessed outside the mansion by Naismith and by Sylvia outside her home . However, the Doctor saves the day by destroying the white point star diamond, and the Master by pushing back Rassilon with his energy as they return back to the Time War. The Doctor is relieved to have survived, but then sacrifices himself to save Wilf, who is trapped within the Gate's venting booth.

The Doctor survives this, and takes Wilf home where Donna is also well . The Doctor then revisits old friends: Mickey and Martha fighting a Sontaran ; saving Luke's life and waving goodbye to Sarah ; cheering up Jack by introducing him to Midshipman Frame ; visiting Joan's great-granddaughter Verity ; revisiting Wilf and Sylvia at Donna's wedding ; and finally to see his first companion Rose before they first meet .

Finally, Ood Sigma and the other Ood sing the Doctor back to the TARDIS, where the tenth Doctor adventures end ... and the eleventh begins!