Nothing that exciting has happened yet, just buildup really
The first couple of pages are from the Magnus Shard that was left on Terra after he broke through the web way gate. He is residing in the Primarch villa under the palace where corax was that time. He thinks on how his subtle body was broken into shards by leman russ and what the other shards and the primary magnus are thinking, and if they know what they are. I presume this is the magnus shard that was combined with Arvida to make Janus, i haven't read that short yet.
Then we are with the main Thousand Sons characters and Lucius on the Torquetum, some kind of geometrically strange weird warp powered orrery that observes the eye of terror. Magus has sent them there to retrieve a bound prophesising daemon called the Iron Occulus. there are a group of human that are the keepers of it, and a load of daemon-pwered robots they use to defend it.
On the way through the structure they go through some mortuary rooms full of dead stuff, various relics and other weird exhibits. They come across an Eldar warrior that is clearly Jain Zar locked in statsis in one exhibit.
Ahriman goes to where the iron occulus is and retrieves it after killing some of the keepers. The daemon is bound in an iron box.
Whilst ahriman is doing this the keepers in the mortuary room and the daemon robots turn on the thousand sons. They and lucius kill a large amount of the robots but its not looking good.
Sobek, ahrimans equerry, does some kind of spell to unleash some really nasty murder daemons that where mentioned in the Chronicles of Ursh. This works and the keepers are killed, and the daemons powering the robots are vanquished.
However sobek isn't powerful enough to control the deamons and they turn on the thousand sons and lucius. They try to use a kind of spell to defend themselves but it doesn't work, and then Sobek is overtaken by the flesh change.
Ahriman arrives in the nick of time and sees the daemons off with the help of the Iron Occulus. BTW the daemon in the Iron Occulus tells ahriman it is to be referred to as Aforgomon.
Ahriman and Hathor Maat freeze Sobek mid flesh change, to see if they can find a way to cure him. They have unsuccessfully tried to cure other thousand sons of the flesh change already, despite Magnus banning them from doing it.
They head back to their ship and go back to the planet of the sorcerers.
Amon is on the planet of the sorcerers. He is considering the ever changing nature of the planet; It is always changing its environment no two vistas or locations are ever the same. The only constant is magnuses tower of the cyclops.
Magnus is talking to Lorgar in the warp. This is Lorgars latest visit and he is proselytising to magnus again on why he should turn to chaos and declare for Horus. Magnus knows of Horuses ascension on Molech. Magnus is fed up and after some talk he suddenly seizes Lorgars iessence in a silver thread and threatens to cut it and let daemons of the warp feed on his essence. Lorgar is powerless to stop him aand pleads with him not to do this, and Magnus lets him go. Lorgars spirit flees back to his body.
Ahriman and Co arrive back at the planet of the Sorceres, and Ahriman takes the Iron oculus to magnus in a thunder hawk.
Thats it so far. Lucius being there but not in the Dramatis Personae makes me think that other characters not listed in it might turn up later.