We've been told countless amounts of time, be it the media, news, comics, or even scientists that time is made out of an infinite number of paths traveling in straight lines. This is almost completely true. In some rare occasions these lines sometimes interlock or even completely merge.
This is what's often left out. It could be deemed the most important part of this entire theory yet it's also the most useless. Interlocking time spaces is in simple terms, merging two identical worlds. Imagine two earths, two moons, two sons, two Milky Way galaxies ext. the point is... the thin line separating these two worlds would only be the subtle differences that allowed them to be close enough to crash into each other.
Now comes this time space. Simply named #3. Yours is a world that is simple and is therefore used as a template when comparing other time spaces. Hence we've adopted the name #3 to it.
#3 is at risk and in possibly only 3 years the world will fall into chaos. As it's neighbor space time G3Hj8 slowly merging... no consuming it. Looking into how each world has multiple billions of years of life, he subtle difference here is that they are 100's of years ahead technologically.
They've long figured out this process and now that they're overflowing with a huge populous, other worlds are now targets for extermination and occupation. There is only one way to stop this forced merge. That is the cube theory.