You are an 18-year-old model high school student. You live a decent life where you are known for your above-average IQ and consistently awarded as the top student in your batch. You have a stay-at-home mother, a younger sister, and a father who works for the police force, whose footsteps you plan to follow after studying criminal justice.
However, you live in a deeply troubled city riddled with crime. One night, you are awoken by screams from your sister's room. You run out to find that an intruder has robbed and murdered your sister but escaped through the window before you could catch them. Despite your family's efforts to pursue different leads, the case goes cold after a few months.
On the first day of university, you randomly chance upon a notebook. After touching it, a God of Death appears in front of you and tells you that you are now the owner of the "Death Note". This allows you to take the life of anyone in any way you want, so long as you write their legal name and picture their face while writing it. You can choose to relinquish ownership of the notebook, but if you do so, you lose all memory of its existence and the God.