The "Game of Thrones," Season 4, episode 7, "Mockingbird," preview, features the return of the Mountain as well as some interesting developments at the Vale and Meereen. The title of the latest "Game of Thrones" episode is a nod to Petyr Baelish's sigil. 

Warning: Full "Game of Thrones" Season 4 spoilers ahead.

According to the "Game of Thrones" Season 4, episode 7 synopsis, "Tyrion enlists an unlikely ally. Daario entreats Dany to allow him to do what he does best. Jon's warnings about the Wall's vulnerability fall on deaf ears. Brienne follows a new lead on the road with Pod."

Based on next week's episode title, "The Mountain and the Viper," Oberyn Martell will get his chance to avenge the death of his sister, Elia. During the meeting of the Small Council in the latest "Game of Thrones" episode, "The Laws of Gods and Men," the Red Viper was particularly interested in learning about where the Mountain was in Westeros, and the "Mockingbird" preview features a quick glimpse of the Mountain. Icelandic strongman Hafþór Júlíus Björnsson will be playing Gregor Clegane in "Game of Thrones" Season 4. The confrontation has been hinted at throughout "Game of Thrones" Season 4 and it looks like "Mockingbird" will place the Mountain close enough to King's Landing to make that scenario possible in "Game of Thrones" Season 4, episode 8.

Tyrion's trial will remain a pivotal "Game of Thrones" storyline after his impassioned speech and plea for trial by combat that closed "The Laws of Gods and Men." It's unlikely his fate will be decided in "Mockingbird" but expect plenty of reaction after last week's dramatic court scene. The "Mockingbird" sneak peek also features Daario Naharis convincing Daenerys to go ahead with a new mission. Based on the "Song of Ice and Fire" series, it appears Daario will be attempt to open trade routes from Meereen to Lhazar. 

It looks like the Hound will train Arya in a fighting style that's more suitable for the armored soldiers of Westeros. Arya tried to stick the Hound with Needle in "First of His Name" and he just laughed off her attempt. Despite his rough exterior, the Hound has something of a heart and it looks like he will try to help Arya in "Mockingbird." While Pod and Brienne weren't seen in the latest "Game of Thrones" Season 4 preview, the traveling companions will make an appearance, but they are still early on in their quest to find Sansa.

Melisandre and Stannis' wife, Selyse, share a moment with the Lord of Light in the "Mockingbird" preview, and her vision could be a glimpse into Stannis' future. It looks like things will get much weirder at the Vale, after the wedding of Littlefinger and Lysa, and that awkward night. Sansa will be subjected to Lysa's jealousy again as her aunt threatens to push her out of the Moon Door.

The "Mockingbird" trailer can be viewed below. "Game of Thrones" Season 4, episode 8 airs on Sunday at 9 p.m. EDT on HBO.

Warning: Full "Game of Thrones" spoilers and "A Song of Ice and Fire" discussion below.

- Will Lysa die in this episode? While I thought the "Game of Thrones" series could slow down Sansa's storyline, the "Game of Thrones" Season 4, episode 7 preview hints at the moments leading up to her death. Like in other "Game of Thrones" plots, David Benioff and D.B. Weiss appear to have streamlined Sansa's storyline without losing any of the impact or character development. Sansa will build a fort and Lysa will catch Littlefinger kissing her in the courtyard leading to her death at the hands of Littlefinger.

- It's going to be sad seeing the Red Viper die in "The Mountain and the Viper." Pedro Pascal has been great as Oberyn and he's a unique character on "Game of Thrones" but his death is important as it sets up Tyrion's escape as well as the deaths of Tywin and Shae.