Steven Universe recently had a shocking revelation that altered everyone's perspective on past events. The recent "Stevenbomb" event, "Heart of the Crystal Gems", was about the consequences of that revelation. I is also about Garnet and her nature, and how it changed because of these events.
Garnet is a living relationship -- the fusion of two other gems, Ruby and Sapphire, and the personification of their love. That love is challenged by the revelation, leading her to "un-fujse" back into her components, who then have an epic argument that ends with Sapphire storming off and a heartbroken Ruby trying to cope. Steven manages to get through to Sapphire that things are not as bad as she feared -- but by that time Ruby had taken off and ran.
The resolution of this is something that has never been seen before on Cartoon Network, in an epic episode where a literal arsenal of Chekov's Guns goes off at once. Much of what has gone before comes home to roost.