This is the 58th novel published by the BBC to feature the 8th Doctor.  His companions are Fitz Kreiner and Anji Kapoor. 

They find themselves in 1930's Spain where someone has been tampering with time.  Well, not time exactly but how events have been perceived, making things appear differently to those who witnessed them.  This causes almost as much damage as if time were changed.  The Doctor takes Fitz to observe Guernica, the focal point of the happenings, while he and Anji document the war to find out anything useful.  Fitz witnesses several account of the razing of Guernica and reports all these to the Doctor.

They eventually discover that the problems are caused by the monster created by a being that has been cut off from his "system."  The being is causing true observations by people that before had seen things colored through their own emotions and belief systems.  The Doctor rights the wrongs and gets on his merry way.  Before all end happily though, he meets up with Sabbath (from The Adventuress of Henrietta Street).

Durruti was dead.

Of there was no doubt, though Anji had heard at least four differing  that versions of his death.  Yesterday the body had arrived back from Madrid, where it was at least uniformly agreed that he had been shot and had later died of his wounds.  He had lain in... well, she supposed it was in state, although she wasn't quite sure an anarchist would approve of the term.  Walking back from the hotel to the TARDIS, she and the Doctor had passed a lengthy queue of people waiting to pay their respects, waiting patiently to reach the open coffin just as they would wait to reach the front of a food queue.  She had found the idea grotesque.

This morning the square was so densely bannered in red and black material that she wondered briefly if the scanner's colour control was on the blink.  The Doctor had assured her it wasn't and gone back to pressing in a lengthy string of characters on one of the keypads of the console.  In an 'ask me what I'm doing' way.  Anji ignored him whilst she poured herself a fresh coffee.

'I really wish this was a mechanical keyboard.' he remarked, glaring irritably at the small LCD above it and pressing the same button several times, 'at least then the click tells you that you have hit the key.'

'What are you doing, anyway?  I thought new co-ordinates were put in there.'  Anji gestured to the opposite side of the pale wood console with her mug.  She leaned her elbow on one of the less populated surfaces and then cupped her chin in her hand, in exactly the same pose as she adopted when she was catching up with gossip at the office.  There was something about the pale wood interior, even down to the scuffs that had begun to appear on the surfaces, that reminded her of work places rather than homes.  She wondered if they should get a water-cooler and a dusty half-dead pot plant to complete the effect.

'They are.  I'm just, well, I thought we'd do a little research whilst we're here, give the old girl time to readjust before jumping on to rendezvous with Fitz.'

Anji raised a single eyebrow at him.  The Doctor busied himself with the keypad even more.  She continued to stare and caught him quickly glance at her through his hair.

'Doctor?  We're five months early!'

'Well, yes, but we'll rejoin him no problem.'

Anji doubted that.  'You said that yesterday but we've not moved anywhere yet.  And if it was so easy, why does Earth 2001 elude you?'  The Doctor looked hurt, so she relented a little.  'So what are you doing?'

Now the Doctor looked at her, smiling that big 'I'm very glad you asked me that, Jeremy' grin and she just knew he'd been waiting for her to ask.  Which meant he had an answer ready and she was about to be told at length.

'Anomalies.  As we saw in Paris, incongruities in the way events are reported or disseminated are revealed when we compare the TARDIS's record with the perceived version outside.'

'How do we...?'

'How do we know the TARDIS version is right?  We don't.  However what I'm interested in for now is finding these moments of divergence, tracing them back and seeing what has caused the different perceptions. I'm working on interfacing the TARDIS with external information sources and then running a comparative check.'

Anji finished her coffee and put the mug on the top of the time rotor.  'So how long will this take?'