Finally, the whole XIII series is being publishing in English (and in the US). Cinebooks has taken on the task of printing this series, with a new volume every 3-4 months. And they are coming to the US a little later after being published in the UK. At this time, 6 volumes are out.
The first 5 volumes comprise one over arching arch. Yes, you need to grasp the idea that each volume is part of a large storyline. The overall storyline is about the man known as "XIII", but within that storyline are smaller arches. Think of some of the serielised tv series of late. Don't expect each volume to be totally stand along.
Volume 3 picks up where vol 2 left off, with XIII locked up in a dangers maximum security prison for the criminally insane. Unfortunately, the doctor in charge of his 'treatment' is part of the conspiracy, and is trying to kill him. At the same time, Colonel Amos, who is heading up the investigation, figures out that XIII is NOT Steve Rowland, but a body double, who underwent plastic surgery and then assassinated the president. He asks for help from Gen Carrington to figure out who XIII really is, and comes up with the Ross Tanner.
In all this, XIII is able to break out of prison, with the aid of Carrington and his aide.