Baddie Russians/Chinese working together, hacked into the Grid exposing all of the data that they hold, and when the American data-sharing programme called Cybershell was going to be linked to the Grid the R/C would have everyone's secrets.
Tariq found the snoops, threw a mock tantrum so that Ros followed him into the gent's and he told her.
Ros then passed it on to Harry via a note that he was able to secretly look at through the side of a glass of water. I thought that was ace.
Lucas was tasked to transport the American computer geek to transfer the codes for cybershell, but Michael was also bugging him for Albany files, so in the middle of the transfer he went to Malcolm's house, who called him John, but passed it off as a made up name to "Mother" and Lucas relaxed again.
The R/C started downloading data files, so Harry ordered them to shut everything off, and that allowed the bad guys to simulate Harry's voice and send Lucas to a bogus rendezvous, where the package got shot and died, but Lucas was a bit "tardy" about getting the ambulance to her once he'd shot the bad guys with the AK47's, hence the comments on here about him going to the dark side.
I'm sure other posters will add bits that I've missed out, and I know I went further than I needed to, but when I got into it, I was enjoying remembering!!!
Boring DH said I should tell you to go to iPlayer. WHERE'S THE FUN IN THAT?!?!?