(The show, now in its 9th season, is based on a series of novels, by Maureen Jennings and is known in Canada as Murdoch Mysteries, re-titled for Ovation.)
Anyway, today (Saturday) they have a new episode that deals with Mark Twain visiting the city. And the character of Mark Twain is played by...are you ready? -- good ol' Canadian boy, William Shatner!
I've seen the coming attractions, and they have made little attempt to make Mr. Shatner look at all like Mark Twain, other than slapping on a large mustache -- actually, he comes across more like William Howard Taft -- but it looks sort of fun.
And now you know. Crank up the DVR. The show will air this afternoon at 4 PM Los Angeles time (7 PM in the East).
I just tracked down a behind-the-scenes featurette on the episode. Here 'tis --