300 years ago, in search for more knowledge, the veil was torn, allowing what was now known as crawlers to come into earth, outworldly creatures that hungered for human flesh. From the veil also came a mysterious energy, and a system to all who came of age, but that was not enough for them to survive the crawlers, and in 300 years, the humans that survived were less than five percent. Alex and his friends discover a way to save the world, a way to fix everything, to use a special system known as the construct system to reconstruct the world at the world core, but when they find it, the core was cracked. Desperate for solutions, Alex is sent back in time to the day he joined the force, those that fought against crawlers, starting from level one, he has to rise and get stronger, in other to find the world core and use the construct system to fix the world before the core is cracked again. But can he stop the things that happened in his past life from happening again? Can he steer clear of the mistakes they made last time?