"How I Met Your Mother" season 9, episode 8 airs tonight: find out where to watch online via free stream for episode 8 of "How I Met Your Mother" season 9, in which the Mother finally returns on the screen.

If you can't make it to a TV to catch "How I Met Your Mother" season 9, episode 8, titled "The Lighthouse," click here to watch it online via free stream tonight.

If that doesn't work, CBS also offers episodes on their website to watch online the morning after an episode airs.

The official synopsis for "How I Met Your Mother" season 9, episode 8: "When Robin and Loretta's conflict escalates, Barney is caught in the middle. Meanwhile, Marshall and Daphne deal with a stowaway on their road trip, and Ted and Cassie try to enjoy a trip to a lighthouse, on the final season of HOW I MET YOUR MOTHER, Monday, Nov. 4 (8:00-8:30 PM, ET/PT) on the CBS Television Network. Frances Conroy returns as Barney's mother, Loretta, and Anna Camp guest stars as Cassie, Ted's weekend date."

In tonight's episode, we finally get to see Cristin Milioti return as the Mother. TV Guide promises that Cristin Milioti's "Mother" will be returning and that the "final minutes are not to be missed," IB Times reports. Fans will see Ted and the Mother together in a "significant flash-forward."

Will Ted propose?

Meanwhile, at the wedding, Ted is dealing with Cassie (guest star Anna Camp), IB Times reports. In episode 6, "Knight Vision," Barney and Robin had put together a list of three prospects that Ted could secure for a weekend hookup. Ted decided to jump on the first girl that approached him, Cassie, but this turned out to be a big mistake, according to IB Times.

Though Ted may have managed to escape her in episode 7, "No Questions Asked," Cassie will be back in episode 8 when the pair "try to enjoy a trip to the lighthouse."

"How I Met Your Mother" season 9 episode 8 airs on CBS on Monday, Nov. 4, at 8 p.m.