Ink Across Decades (слэш)

When Harry finds the Half-Blood Prince’s Potions book in the ruins of the Room of Requirement, he has no idea it will change his entire world.
Through ink and time, he begins corresponding with a seventeen-year-old Severus Snape - while the thirty-eight-year-old man lies in a coma only floors below.
What begins as cautious conversation slowly turns into confession, friendship… and something far deeper.