If you watched 'Split', you'll recall that James McAvoy's layered performance culminated in a freak of nature being known as The Beast.
The movie was built around the character coming to the front of his multiple personalities, and when it finally hit, it was... well, terrifying, to say the least. 'Glass' picks up pretty much right after 'Split' and shows McAvoy's character - Kevin Wendell Crumb - now in a mental institution where Sarah Paulson is helping to treat not only him, but Bruce Willis and Samuel L. Jackson's character.
The trailer also gives us far more information about what the plot will be, where Anya Taylor-Joy fits into the scheme of things, and how it is that they're all put together. In fact, the trailer's kind of spoilery so if you want to go in cold to 'Glass', it's probably best if you don't watch the latest trailer.
Here it is, in any case. 'Glass' arrives in Irish cinemas on January 18th, 2019.