Neo, Trinity and whoever the hell Neil Patrick Harris is playing are plugging back into the "real world" for the 'Matrix 4' -- 'cause they're back on set, and cameras are rolling again. Leading man Keanu Reeves along with his costar and on-screen lover, Carrie-Anne Moss, were both spotted in Berlin this week and presumably heading to their trailers, as they looked ready to get back into character and start filming, after several months off due to 'rona.