In an alternative universe,there are these things called 'Siro'. What is a Siro? Well they are these creatures who look exactly like human though they have cool powers or something,But these creatures are born with a twin-like human (It'll be explained later) and let's called their twin their 'owner' (not in a sexual way) and without an owner they can't use their powers,and also they have to live inside a 'mark' most of the time which will also be explained, anyway for the owner to use their Siro's abilities they have to say some kind of hocus pocus or something idk-anyway they all have unique powers.

Siros are almost identical to their owner,they're basically twins,the mom gives birth to both her child and a Siro, they share the same face,and blood too. A person born with a Siro will have a mark on their hand or cheek those who aren't born with one won't have any mark on their hand or cheek. Most of the human population have a Siro, but, there are some people who don't have one,there is a good 95% chance that someone will have one,while the other 5% don't.

In this story,our main character is Akirō Hatsume,with a very caring brother named Akirō Hatori,our main character,isn't born with a Siro,so her life has been a lot of people making fun of her for not having one,however,one day,she was walking down a path when she saw something unbelievable :0 and guess what it was?A wild Siro!

Now,to explain things simply,wild Siros are Siros not wanted by their past owner,so they basically abandon their responsibilities. Useless information: It's not possible for a person to have more then one Siro,when someone wants to make a bond with a wild Siro,that Siro will have to decide whether or not they want them as their owner.

Another useless information: Since Siros look exactly like their owner, since they're like twins,when they break their bond with their owner,they'll still have the face of their past owner,even if they make a bond with a new owner,their blood,face,memory or personality won't fade away.

Another useless information: When an owner of a Siro dies,their Siro will die along with them,it is the same thing with the Siro,if they die,their owner dies too,they basically share the same fate,and what if a wild Siros' owner dies?Well since their bond is already broken,the Siro won't die and this Siro,was just not any Siro, no,no,no,it was an ultra legendary Poké-I mean Siro,nicknamed 'Snow Cat' or 'Snow Godess'(known for almost being extinct)so of course,our main character when sees this Siro,asks if they want to be their Siro since she doesn't have one,at first,they seem a bit grumpy,but then as they spend the day with her they start to get along, they almost agree until she meets Hatsu's brother then she feels like she remembers him from somewhere ,although it looked like they knew each other.

Hatsume says that she'll give this Siro a new name,however,the Siro INSISTED on being called the name her past owner called her,which is 'Megami Yukino' (fun fact,if you translate this name from Japanese to English you'll get the name 'Snow Godess') and she also insisted that she would be called 'Yuki' for short,Hatsume agreed to call her that, anyway, the next day, it's time for Hatsu to go to school.

A lot of people were shocked knowing she had found a wild Siro,some even thought she forced her to make a bond with her,but she ignores them and continues with her day, and here is the part where we meet the side characters-Hatsu's friend (doesn't have a name yet)and with another friend (also doesn't have a name yet,oh also there'll be way more characters in this later on)she tends to go as her usual,when boom anime cliché boy moves into school on the day exactly after she has a Siro cause yes,anyway the boy(don't have a name)has an older sister,and turns out that this boy is actually Hatsu's childhood friend,and that she used to hang out with him and his older sister all the time, but they had moved away when she was young, and then she confronts him trying to say hi but the boy says he doesn't remember her. Then,she asks his older sister,she says that there was a car accident which caused him to get amnesia(yes,a car accident,again really poorly written story)but Hatsu doesn't give up,she tries to get along with him and tries to get his memory back but all her attempts tend to fail, and then,when she goes home that afternoon, she finds her brother's corpse.

Right as she opens the front door,and yeah she gets an emotional breakdown, she call the police and a few days after her brother's funeral, she goes to find who killed her brother cause she has A LOT of time and motivation to do so,and also cause she loves her brother but mostly time and motivation, and yeah her homies help her cause they homies:)

(and also the boy was dragged into this mess cause of Hatsu)a few days later that, the boy's sister is suddenly missing,with no trace of her anywhere,not even a note. The night before that incident,the boy and Shinzou had a huge fight,though it's unknown why they were fighting,when asked about it the boy refuses to answer,saying it's 'personal' and that he doesn't want to talk about it.

Let's introduce another side character-his name is Rioto Takeshi and he has these weird looking glasses on cause he has a super rare Siro which allows every indivisual who looks into his eyes turn into stone(Also he's a detective cause yes)anyway he's helping Hatsu solve the crime cause it's his job-he did indeed told Hatsu to stay away from the situation but she was too stubborn so yeah-a bunch of high schoolers solving crimes and he's okay with it-anyway-sooner or later Hatsu meets his ex wife which he got a divorce from for unknown reasons.(totally not suspicious:))

She tried to fix and patch things with him,and she succeeded? Well anyway there is this scene where Takeshi is talking to her saying 'Please forgive me,I promise I won't do those things again,I know what I did was bad and I did it knowing how you would react,but i can be a better person'(why do all these lines sound so cliché and cringe-)

Anyway plot twist comes turns out there is this group of random serial killers who want to kill EVERY snow cat in existence cause yes,also one of the members is Hatsu's fathe. The reasoning behind this was that this guy was abandoned as a child at the age of 14. However, a man came and said that he will give him food and shelter and also teach him combat, but in return, he had to do a job for him. When he was a child his parents were really toxic,fighting all the time,and didn't try to teach their child anything, including good or bad, so he didn't knew what he was doing. But then he met Hatsu's mom, ✨AdDiNg CoLoUr To HiS gRaY wOrLd:)✨, so Yamada's(that's his name) job was to seduce lé cause he is ✨InCrEdIbLy HaNdSoMe✨(this is the only excuse i have okay)and on their first week 'dating' he would've killed them,but he didn't kill Hatsu's mom cause plot armour, he hid this fact from the man so he wouldn't kill him, but then Yamada proposed...?Got married...?Had kids...? Wow the man must be doing a shitty job not knowing his most favourite adopted son is literally married and has kids.

The man eventually FINALLY finds out about what Yamada has been doing(Jeez man didn't take like 10 years)but doesn't kill him and gives him a chance to live(plot armour)he threatened him by telling him that if he doesn't do the job,he himself will kill her and his kids,including Yamada himself. But if he did the job himself he'll let him and his kids live and if Hatori somehow saw him, he could throw all the images of him away,his name was fake (his real name is Koketsu btw) so he didn't have to worry about that,the man paid him money for killing i guess?So he didn't had a job and he said he had a different job from his wife who somehow never found out after 7 years of marriage- anyway, they lived in a place where people didn't pass by much and they didn't have any neighbours,so all the possible evidence could be erased (also he's a pro at hiding bodies and cleaning blood in a short amount of time)

So Yamada chose to do it himself, HOWEVER, his wife found out about his plan while eavesdropping on them calling, she only heard about the plan to kill her, not the choice he was given and thought that her children could get killed, she knew she couldn't defeat him in a fight, she knew that if she tried to run away with them she'd only end up killing them all, so, she told her siro,Yuki, that she wanted to break their bond with her (Yuki knew what was going on) Yuki said that she should run away with them but she told Yuki that it'd only get them all killed, so, Yuki and the mother broke their bond. Yuki then went to Hatori's room and told him to get Hatsu . (who was like 1 year old)