TV highlights: Led Zeppelin's Robert Plant comes to 'The Colbert Report'

While Maggie and Richard's relationship deepens, Alex and Meredith's does as well, much to the dismay of a jealous Jo, on "Grey's Anatomy" (ABC at 8 p.m.). The remains of a right-wing radio host are found in a storm drain on "Bones" (Fox at 8), and, with the help of intern Rodolfo, the investigation reveals a number of worrisome extracurricular activities that narrow down the suspects.