Tonight, I finished viewing 2015's The Invitation directed by Karyn Kusama, and wow, what a gut punch of a film.
It's a drama/thriller/horror film about a group of lifelong friends being invited to a dinner with something unusual just beneath the surface.
The Invitation deals heavily with themes of trauma, PTSD, and loss. If you're sensitive to these issues, maybe give it a pass, but if you're into deep tissue emotional stuff, give this one a go.
