A few games ago the players ran in to some serious trouble from a hit team sent to get the heavily speed-modified member of the team. From that they were able to trace that they were in pretty deep, and a bunch of other people with similar mods were on their tail.
After a nearly lethal encounter with one of these speed-augmented people, they learned from another that there is a commune of these people trying to remain hidden from the company that created them because they were being used as expendable troops in the current corporate war. However, the leadership of this cell has gone crazy it seems, and is now purging members as well as hunting down non-members who were created by the same company.
So the players hike off to Iceland to find the commune, negotiate their way in, and determine that Arasaka has planted a brainworm ghosthack in the leadership of the cell. The cell has also discovered that the speedware they were equipped with causes permanent neurological damage (a metagame tweak to make players remove their speedware because it was unbalanced), and are now researching new replacement speedware.
The party netrunner forces the AI system at the commune to reboot. This gives them about two minutes to either (a) talk to the leadership and explain the brainworm situation to them or (b) head downstairs and take out the AI mainframe. Being a more combat oriented team, they took B and went after one of the three leaders in the Mainframe control room. Turns out that leader was a weird full conversion and to quote one of the players "Shiv's eating 1d4 investigators per round!"
In the end they take out Shiv, blow up the mainframe and THEN negotiate with the elders. With Arasaka having the location of the commune, they ask the players to take an EMP device with them to an anti-Arasaka activist they know and then bring him back to Night City where he can get a team together to use it to wipe out the Arasaka mainframe.
Next thing you know, they rescue this activist (none other than Johnny Silverhand) from a riot, and head back to Night City where they drop off Johnny, Santiago and company at the Arasaka towers, and then split when the gunfire from Adam Smasher gets nasty.
They were flying out of town when Johnny triggered the EMP device, which turned out to actually be a small nuclear weapon, in the Arasaka basement. That in turn triggered Arasaka's larger nuke down there, and the corporate centre of Night City starts to collapse in a white fireball as the EMP pulse takes their AV out of the air.
They all wake up in the hospital, and the fourth Corporate war quickly spins down as several nations re-establish their power over the corporations.
Next game we head back into the Heaven Over Mountain storyline as they get involved in the merger of Petrochem and Orbital Air and the building of the first Space Elevator.