Curious about the Doctor’s frequent mentions of how traveling with Evelyn Smythe calmed him down, Melanie talks him into paying her a visit. Three years after the invasion of Vilag, Evelyn – who left the Doctor’s company some time ago – is now married to Rossiter, who heads up the new global government. But all is not well even in the wake of the invasion of which the Doctor and Evelyn tried to warn everyone on their earlier visit; the leftover alien technology has become a subject of intense controversy, with Evelyn heading up an effort to have it studied and exploited for the benefits it could bring. The most vocal opponent of this viewpoint is Rossiter’s daughter, Sophia, who leads a faction that wants the alien technology destroyed. But mere moments after the Doctor and Melanie appear at a ceremony marking the anniversary of the attack, it appears that some of Sophia’s opponents are more prepared to take action than others. When the first shots ring out, the Doctor and Evelyn both think it’s an attempt on Rossiter’s life, but when the Doctor rushes to help Rossiter, Evelyn and Melanie are kidnapped. The Doctor and Rossiter set out to track them down and rescue them, and find that the Doctor’s companions, past and present, aren’t the only ones who need help.
written by Paul Sutton
directed by Edward Salt
music by ERSCast: Colin Baker (The Doctor), Maggie Stables (Evelyn), Bonnie Langford (Melanie), Gabriel Woolf (Principal Triumvir Rossiter), Rachel Pickup (Dr. Sofia Rossiter), Patrick Romer (Dr. Andrew Szabo), Simon Watts (Dr. Sebastian Lawrence), Matt Dineen (Jenner), James Parsons (TV Interviewer), Sylvester McCoy (The Doctor)
Timeline: for the Doctor and Mel, after Catch-1782 and before Time And The Rani; for Evelyn, after Arrangements For War and before A Death In The Family
LogBook entry & review by Earl Green
Review: A direct sequel to Arrangements For War, Thicker Than Water is utterly fascinating stuff, a different scenario for Doctor Who and a different perspective on the Doctor. The Doctor gets less “ear time” in this story than Evelyn and Melanie do, and their discussions of the Doctor are like those reserved for a troublesome but beloved relative. I was almost worried that Thicker Than Water was going to lock the writers of future audio adventures into a specific fate for Evelyn, much as the New Adventures authors had to bend mightily to bring Ace’s story to a resolution that matched up with the destiny laid out for her as early as the novelization of The Curse Of Fenric. And while this story does, indeed, bring us to the end of Evelyn’s journeys in the TARDIS, it doesn’t fill every gap in between or even necessarily tell us at what point this will happen. 
Indeed, there’s a very surprising scene right before the end of the story that makes it very clear that there are more adventures of the sixth Doctor and Evelyn yet to come.
Production-wise, Thicker Than Water boasts some excellent sound design and surprisingly modern music, along with a great cast, many of them returning from Arrangements For War. The story gets going fairly quickly, assuming that you know what happened in Arrangements and not spending a lot of time recapping that story; depending on whether or not you’ve heard it, you could be approaching this story with quite a narrative handicap. But the ongoing story that we pick up in Thicker Than Water is worth the catching up.