'All across the universe, the Doctor is hailed as a hero, a benevolent force, the man who fights the monsters, topples the dictators and frees the oppressed. Repercussions demonstrates an alternative side to this. What if, whilst doing these good, even great, deeds, the Doctor is unwittingly changing the Web of Time. Giving people knowledge they're not supposed to have. Empowering races that should have remained in the dark ages. Overthrowing the evil that, had it continued to flourish, might ultimately have brought together a greater force of good to eradicate itself.'
Source: drwhoguide.com (http://www.drwhoguide.com/whotrip11.htm)