What is it about?

I'll write one in the here and now. Ive watched a few times but not lately

The prologue tells us that D3 Corporation [Injoke as thats the Game series' publishers] has released a virus which has made dead people into zombies rather than bringing them back to life normally which was Doctor Sugita's intentions. We then see two guys shooting zombies outside a building but one of them is getting shot but the bullets arnt impacting. We see a party happening and then the zombie that couldnt be stopped and some others storm the party and they all start fighting. We then see Aya and her fat friend whos name I dont remember walking not saying anything. Aya goes into the building and starts fighting the Zombies. After the fight there is only Aya and the unstoppable zombie left whilst the fat friend gets supplies. Aya asks the zombie where she can find Saki but then a woman on a bike crashes in and shoots the Zobmie. Aya and Reiko start fighting until the fat friend bursts in saying that humans shouldnt be fighting because of how there is zombies on the loose. Reiko says she knows where to find Saki so the three of them start walking.

They come to a clearing with a few buildings and start a camp fire. The fat friend starts eating but neither Reiko or Aya eats anything. The fat friend explains to Reiko how Aya hardly ever speaks and that he has never seen her smile because of how she saw her sister [Saki] kill there father. He shows Reiko a picture of his sister that he hasnt seen in many years. The three get shot at by a couple who thought they were zombies. They all sleep in various places and the couple are shown to have sex. We then see zombies approaching. Zombies then approach the couple and the man is bitten to death and when trying to drag him out, the woman pulls his arm off. As Aya sleeps she dreams of when she saw her father get attacked by Doctor Sugita and some people from a clan. Saki then delivers the final blow to kill him. A zombie then approaches Aya but she suddenly wakes up to slash him. Another comes from a window behind and Reiko shoots it. The two get out of the building to see Zombies swarming the area. We see the fat man urinating up against a wall where the couple who are now zombies approach him from either side and Reiko rescues him by shooting them.

We then see Doctor Sugita injecting blood into a corpse. The corpse starts to animate and it falls on the floor. Sugita calls it to him but its evident that the body has turned into yet another zombie so he strikes it down shouting No. He then says how the Imichi Clan blood should solve the problems with his experiments so he needs to use Aya's blood because she was the chosen leader by her father. Sugita calls Saki and we then cut to see a man running in a warehouse. He comes to a stop and catches his breath but then Saki in her usual attire of a school uniform jumps down and kills him with her sword.

[Im not 100% on the order of the next paragraph but all these events happen in this part of the film]

We then see the three protagonists in the daylight walking into a warehouse . The fat man says he shall go look for supplies. Aya and Reiko come across a doll. Reiko picks it up and looks around. She then sees a little girl. She calls to her but the girl runs away. Aya goes round the back of the girl and the girl runs and hides. Reiko gives her the doll and hugs her saying how its all fine. We then see Doctor Sugita feeding a girl some food and hitting her for not obeying him when he says she shall be used soon. We then see Reiko and the girl. The girl is running around and Reiko gives her a bracelet that used to be her daughters. We hear that the girls name is Maria. Doctor Sugita has the girl who we now see is the fat man's sister on the table. He injects her with some blood that corrupts her red blood cells and she opens her eyes. We go back to seeing Reiko and Maria where a zombie comes out and Reiko shoots her. Maria gets scared and runs off. Reiko runs after her.

We see the fat man looking around for supplies where his zombified sister is behind him spinning a spiky ball on a chain. She throws it but it misses him. He turns around and the two fight a bit and she gets him up against a wall where she is trying to bite him. He gets the picture of her and tries to make her realise that its her brother. Aya drops down and then those two fight. The fat man sees his zombified sister and only friend fighting. In a supposedly emotional no sound moment he looks at them, grabs his knife and then lunges forward digging the knife into his sisters stomach. She dies and then the two hear Maria screaming. They run and see Saki holding a sword up to Maria's throat. I think she got bit on the hand by the zombie Reiko shot for her earlier. The fat man runs to attack Saki but gets knocked down. Saki and Aya fight while Reiko comforts Maria. Saki knocks up a load of dust into Aya's face and escapes. Reiko says how Maria is hurt.

They find a hospital and Maria is on a table. The fat man says he shall go and see if any nurses are around. He wanders around the hospital and sees a lot of Zombies trying to get into the door. He also comes across a zombie nurse who starts chasing him with a knife. Aya gets her knife out and puts it next to Maria's head and tells Reiko that she will be a Zombie soon so she should be killed now before it happens. Reiko puts her gun next to Aya's head saying that she would shoot if she hurts Maria. They then hear the fat man screaming. He is still being chased and runs past a room, Aya then comes out with her sword and decapitates the nurse. The body keeps on moving for a few seconds before dropping to its knees infront of the fat man. He and Aya go back into the room where he says that they need to get out of there asap. Reiko says she wont kill Maria because she had to kill her daughter before because she became a zombie and she wont do the same again. Reiko tells Aya where to find Saki and her and the fat man leave. Maria breathes her last breath in Reiko's arms saying 'Mommmy'. She then dies and a load of Zombie's then storm the room. Reiko starts shooting them when Maria then rises up, Reiko turns round and shoots her point blank in the face.
We see Aya and the fat man walking in a field towards a large building. They enter and Saki and Doctor Sugita appear from a staircase. They all talk and then a lot of Zombies appear for Aya to fight. The fat man leans up against a wall but falls in revealing a secret door. He sneaks into a door where Doctor Sugita is watching CCTV and the fat man runs at him with a knife but fails and gets hit a few times. A zombie then appears and starts attacking Doctor Sugita by crushing his eyeballs into there sockets. Sugita and the zombie start fighting on a table and the Fat Man then dives a sword through there bodies piercing both of them. The fight with Aya gets more intense and then Reiko appears and the two start kicking some ass. Too many appear and Reiko gets swarmed upon. Aya does something similar to a kamehameha which kills all the zombies. Aya runs over to Reiko where Reiko has been bitten many times. Reiko puts the gun to her head and kills herself. As Aya mourns over the body Saki appears.

The two sisters go out into the field and start fighting. Aya gets knocked back at one point and we see the two as young girls practising fighting, Aya being chosen as the stronger one and being head of the Imichi clan, Doctor Sugita approaching Saki and the full death of there father. Aya rises back up and then the fight goes on for a long long time. Its on Youtube if you want to watch. But anyway the two stand and then we see Aya had blood on her sword and Saki collapses. Aya goes over to her and holds her in her arms screaming why and Saki until Saki smiles and dies. We then see Aya and the Fat Man over a burial site in the field where a makeshift tombstone out of Aya and Saki's swords were a crucifix. Aya stands up to leave but then turns back and takes both of the swords and smiles to the fat man. They walk off into the distance, Fade to black. Then an epiloge saying Tokyo, Japan 20XX. We see Aya with two swords jump into the air with her being shadowed by the moon. She dives down and we see zombies reflected in her eyes. She smiles and slashes the screen where the logo appears on screen.

Phew.

Girl in bikini killing zombies. the plot is incidental at best.