One day, after Dr. Lang of the RNF Foundation created an anomalous entity called One More. Several armed agents and researchers from the SCP Foundation crossed over to the RNF world through portals created by the One Mores as they traveled between dimensions.

And now, several members of the RNF×SCP Foundation cooperative team have assessed the situation and decided to work together to contain all the One Mores.

Following the Backrooms blueprints left behind by One More, they create a portal to move to an infinite space 3,000 times the surface area of the Earth.

Then, one day, while they were repairing the Backrooms portal device.