Excelis Rising (Doctor Who) by David A. McIntee

A millennium later, the Sixth Doctor revisits the planet Artaris, a world he once knew deeply. The city has changed dramatically, shrouded in mystery and filled with echoes of its past. Amidst the towering structures and the remnants of previous civilizations, the Doctor becomes embroiled in a plot that threatens the very fabric of this alien society.

As he navigates through political intrigue and technological wonders, an ancient threat looms, forcing the Doctor to confront not only the challenges of a time-displaced society but also his own memories of the planet. With allies and foes waiting in the shadows, every decision he makes could alter the course of history for Artaris and its inhabitants.