Loss of Memory

Self-defense

Transformation

Destination

Yuka's Memories

Lost Memories

A Sudden Visitor

Female Visitor

Messenger

One Strike

Clash

Reinforcements

Thus the Girl Died

Father of a New Race

The Girl's Past

Living Together

Meet Again

Offspring

Prosperity of Death

Teacher of Horns

Nyuu Caught

Ditched

Lebensborn

The One Who Has Freedom

Modification Surgery

Connection

Knot

Detection

Nyuu's Past

Promise

Scream

Lies

Whisper

Kanae

Flashback

Disposal Order

Parting

Attack Pretext

On The Run With Common Front

What Shan't Be Seen

Peeing

Hide and Seek

The Project

Contact

Panic in Maple Inn

Unforeseen

Copying Kanae

Tears

Kurama's Daughter

Ways, Choices

Sand Castles

Mariko

Girl's Fun

Papa for Two

Lab's White Walls

Tests on the Living

The Annunciation

Final Choice

Deeply Held Resentment

Grin

Blaze of Glory

Midway to Heaven

Humanity's Fall

Backup Measure

The Heart and the Uterus

Isolation

Heartbreak

Wish Upon Tomorrow

Anna

What are you Searching For?

God of Death

Animal Scent

Another happy future

Does sake make one drink or make one drunk?

An Unachieveable Retribution

Can Life Merely Be Despair?

Boy Meets Girl

Helpless

My Creations

Communication

Outcome

Reminiscence

Broken Angel

Family

The Insincere Night Sky

The Palm

Memories and Gunshots

Death Maze

Stupidity

Bewilderment and the Sea

Lack Communication

The Researcher's Pride

Tear Shed for the Other

Everyone's Hell

Dawn of the Long Night

The Ocean to the Past

The story involves human mutations called "diclonii", who are born with horns on their heads and possess telekinetic powers, in the form of invisible "arms" called vectors. The power of these arms vary, but they can stop normal bullets and deflect some others. The number of them differ with each diclinous, as does their full range. 
The tendency for violence among diclonii is high, especially as they grow older. As children, their violence stems from a certain playfulness, unlike the absolute hatred of humans in their later years. Diclonii are rare, as they are the members of their species that are able to reproduce naturally. 
Silpelits are more common. They are the offspring of two humans, the male of which has been infected with the mutation. Interestingly, only males can pass on the genes, and all diclonii and silpelits turn out to be female. Certain scientists noticed an increasing number of babies with horns being born, along with those children murdering their own parents and others, and tried to contain the spreading and find out the cause by placing them in a Facility in cells where they are subject to inhumane experiments to test their abilities or where they await execution for being too dangerous. 
The main non-mutant character in the story is Kouta, who ends up becoming increasingly involved with one diclonius in particular, the main mutant character Lucy, the only pure diclonius, as she seeks a way to infect or kill all of humanity. Lucy has a cruel and unsettling past, and she has long since lost her empathy for humans, except for Kouta. 
However, Director Kakuzawa, who has diclonius ancestry although he doesn't have the vectors, has plans to mate with Lucy and start a true diclonius race. If Lucy is found and he manages to do so, humanity will be nonexistent. 
Kouta and Lucy's lives have been intertwined since their childhood, but not necessarily in a good way. And after the virus is airborne and spread across all of Japan, what is the fate of humanity and who holds all of the answers? 
Note: Chapter count includes 6 extras.