It isn't natural for two souls to inhabit one body. It could destroy the mind, destroy a soul, or destroy everything. So one has to dominate over the other; but there is consequences. Two girls are pulled into a world they know by heart: one accepts both memories, the other represses. They have to survive the onslaught of titans, lies, love, and terror without trying to change anything too drastically, but that's hard enough as it is.