
After Walter's mind is damaged by Windmark's telepathic probe, the Team goes to Walter's old Harvard lab to find the information they need to defeat the Observers.
Thus, far, it appears that TPTB are keeping their promise to keep things fast-paced, with no filler eps. Should be cool to revisit the lab, as we begin to find out what happened after September's warning to Walter (seen in the S4 finale).