Ensemble-wise, it’s a deep bench, with polished turns from Seth Numrich as an oily James Murdoch and Dylan Baker as a flinty lawyer, both doing the banality-of-evil soft shoe quite nimbly. But the hero of the day—in character and out—is Toby Stephens, who seems to be having fun as he carries this long and busy chronicle on his shoulders. Naturally charming and energetic, with inexhaustible Everylad comic appeal, Stephens uses considerable technique and charisma (he’s a London stage fixture) to fine effect, tossing off Rogers’s overstuffed dialogue and stilted diatribes with style, finding the humor and heart at every turn. Even if Corruption is a mixed bag, the real-life Watson must be pleased that after years of getting slagged off in the press, an admiring playwright prints the last word.