Terrance Dicks is a name well known to fans of "Doctor Who" novels - he's written or novelised dozens of stories for the franchise. He was also the man given the unenviable (I feel) task of writing the first ever story to feature new Companion Martha Jones, even before she'd had her screen debut ! His Made of Steel does a good job of capturing the essentials of Martha's character (Dicks was apparently shown scripts of the first few episodes in order to learn about Martha).
The Doctor and Martha Jones have been visiting the Cretaceous period and decided to make a quick getaway when a T-Rex appears. They journey to present day Earth to find that Cybermen (whom the Doctor believed had all been destroyed at the Battle of Canary Wharf) have been teleporting into buildings and stealing electronic equipment. The Doctor takes Martha to the Royal Hope hospital, where she worked before she started travelling with him, and where they have a confrontation with a pair of Cybermen in the car park. They are nearly captured but the Cybermen suddenly disappear, due to a fault with their teleportation technology. The Army wants to get hold of the Doctor in order to ask for his help, so they arrest him and capture the TARDIS, leaving Martha behind. At the Army Base, the Doctor realises that the Cybermen were built on Earth, not in the parallel universe from which most of the Cybermen arrived in "Army of Ghosts" so they were contaminated with "Void stuff" as the other Cybermen had been, which is why they were not sucked into the Void during the Battle (in "Doomsday"). They have been using teleportation devices stolen from the Torchwood building in Canary Wharf to help them gather together enough equipment to create a portal into the Void from which they intend to release the Cybermen who were trapped inside. But they don't know how to open the Void, so they try to capture the Doctor to do it for them.
After the Doctor is arrested, is captured by the Cybermen who take her to their secret base. They discuss whether or not to kill her, but decide to hold her hostage; whilst they're still talking the Doctor rings Martha on her mobile and tells her where he is. Just as Martha's about to tell the Doctor where she is, the Cyberleader snatches her phone and destroys it, then sets in motion a plan to attack the Army Base where the Doctor is being held. He, however, figures out that the Cybermen are at the Millennium Dome, but before he can head off there, six more Cybermen, who had been kept frozen since the Battle of Canary Wharf, attack the base. The Army manages to destroy all but one of the Cybermen using a newly-prepared weapon they had on hand in case Cybermen should attack the base again. The Cyberleader tells the Doctor that they'll kill Martha unless he helps them, then vanishes.
The Army plans to attack the Millennium Dome, and in the meantime the Doctor persuades them to let him have the TARDIS back and he manages to materialise inside the Dome. The Doctor apparently co-operates with the remaining three Cybermen, and opens a portal by linking up their equipment to the TARDIS. But the Cybermen soon discover that the Doctor's portal doesn't lead to the Void, but rather to Prehistoric Earth where the T-Rex that had earlier caused the Doctor and Martha to make a quick getaway, appears and kills the two Cybermen. Martha damages the force-field generator that has been preventing the Army from entering the Dome, and the Doctor uses an electrical cord from it to fry the Cyberleader. The Army enter the Dome only to discover that the Cybermen are all gone or dead, and the Doctor takes Martha off to somewhere "peaceful".