Each government rallied humans with special psychic powers and fought back against the dimensional monsters and succeeded to close the gates, however, they had to make great sacrifices. Henceforth, the heroes with special psychic powers were named 'CLOSER' since they can 'close' the dimension gates, and the war against the dimensional monsters were named 'Dimensional War'.

18 years before

Dimension gates opened all around Earth and through these gates, dimensional monsters raided the whole world. Normal attack weapons of mankind couldn't do any damage to them so mankind was helpless against the dimensional monsters, just had to watch them devastating the cities. However, the dimension gate did not cause only a bad influence. Very few humans were influenced by the 'Phase Force' emitted by the dimension gates and it granted special psychic powers.

Each government rallied humans with special psychic powers and fought back against the dimensional monsters and succeeded to close the gates, however, they had to make great sacrifices. Henceforth, the heroes with special psychic powers were named 'CLOSER' since they can 'close' the dimension gates, and the war against the dimensional monsters were named 'Dimensional War'.

Overcoming the pain of the Dimensional War, mankind quickly rebuilt ruined cities into new cities. And an affiliated organization of UN named 'UNION' carried out the study of the assembly of the Closers and the research of the gate, all to prepare for the dangers of the dimension gates. Soon found out that the dimension gates open when the Phase power reaches the singularity. However, still far away from fully understanding the Phase Force and the dimension gates. The UNION is focusing on finding and training New Closers to prevent another Dimensional War.

At that time, each gate around the world suddenly began to shake and the invasion of more powerful dimensional monsters followed.

The story of starts from the normal daily activities of special teens, teens who are assigned to the New Seoul's Closers team named 'BLACK LAMBS'.

You are an agent of Black Lambs, now you are the Closer who will defend 'New Seoul' from the invasion of dimensional monsters!

When the Vultures were allowed to manage the phase-users, they started to call and use them as a 'disposal unit'. Among the 'disposal unit', the one at the New Seoul branch named 'Wolfdog' team is known as the ablest and cruel team.

After the dimensional war, UNION continued their study and experiments on Phase Force...

However, the Cost of studying was enormous, and the supports from powerful nations were decreasing. So UNION accepted the request of civil industries to produce and sell the phase gears with no other choice. However, because of the extreme secretiveness of UNION, most of those industries gave up.
Vultures is the only one that survived and monopolized the market.

Vultures kept growing and became a huge company that can now affect UNION in some parts.
Vultures requested UNION to allow them to directly manage the phase-users for the further study on phase force and the collection of the debris of dimensional monster.
UNION at first refused but soon allowed them because of their huge reward.
However, soon, vultures loosed almost all phase-users because of the mission to eliminate raged human-type dimensional monster.

The leader of the Wolfdog team decided to manage that monster in his team rather than eliminating her.
Besides, he did his best to gather the team even releasing Nata who was locked alone in the room because of the accident he made.
Finally, the New Wolfdog Team starts to show their ability in the dark of the New Seoul

UNION created the new closers team consisted of phase-users using the gear of dimensional monsters named 'Wildhüter' that only works for the direct order of headquarters. The team is staying in one castle in Germany, and they are the secrete team consisted of teacher and student.

Teachers with tragedy and students with their fate are fighting against their destiny.

Lunatic experiments conducted by some scientists during the dimensional war created children who were born with a harsh destiny.
These kids with special power grown as the will of the adults, without any pleasure of kids.
For these kids, they needed an adult who they can trust and follow.

Some unique closers have a unique ability in UNION.
They always took the harsh missions because their power was unreplaceable by other closers, and this made them confront tragedy all the time that follows them forever.
Adults who made them attack their loved ones.
For adults, they needed someone to take care of their scars.

Finally...
The Wildhüter Team that is not a family or company, born as a school.

Trash Island, the island full of acid of high-class dimensional monster.
The entrance has been restricted for a long time, as no one or no monster can survive.
However, there are people left behind by someone on that island.

Even on the trash island where no one can survive, there were still people living there.

Abbadon, the dimensional monster that changed Busan into the city of disease during the dimensional war.
A hero appeared like a comet made him sleep like an eternity on one island.
However, that body kept spread the horrible poison,
made the island a trash island where nothing can live.
But even on that island, someone is still maintaining their lives.

If the people on the island are dead, new and healthy kids came.
Nobody knows what was the purpose or intention of that.
They just get supplies from volunteers and administer of the island through errand-center and broker,
trade with a smuggler and survive day by day.
For them, some special cargo has arrived.

Soon...

An errand-center receives a request to go outside of the island.