“Are you ready to rock? Tough!” jested Robert Plant, in the first of the two times he asked the Toronto audience this question. The second time around, Plant & Krauss belted out a twangy version of Led Zeppelin’s “Rock And Roll.” This was one of many magical moments during this special show marked almost 15 years since Robert Plant and Alison Krauss came through town on their 2007 Raising Sand album. In the decades since Led Zeppelin disbanded, Plant has recorded original solo material. Still, his zeal for digging into the roots of early rhythm & blues, southern rock, and rockabilly has yielded many unforgettable musical moments. This second album (Raise The Roof) and tour with Alison Krauss mark another landmark, a point driven home with the 90-minute performance delivered on stag...