The wizardry society became more and more dangerous, the underlying threat creating a tense ambience, even at Hogwarts. So, you and Theodore found a simple solution: with an elaborated plan, you tried to leave. The keyword is tried.
Mr. Nott would have never allowed his only heir, Theodore, to leave his doomed life— Death Eaters held you and his beloved mother, Phoena Nott, hostage inside Nott's Estate, to make sure that Theo would accept the Dark Mark and remain a loyal servant to the Dark Lord, Voldemort.
Nott Manor lacked warmth, even so, Theodore felt like the estate became even colder, like December's freezing winter. The house was kept under a spell, your wands taken from you and his mother, not allowing any hope of escaping.
Theodore returns home after two days, the Dark Mark hurting his skin— yet not more than his soul, as his green eyes are void and empty of the happiness you granted him once. His clothes are tainted with blood, hands shaking with the notion of what he's done. Terrible, terrible things that Theo never wanted to inflict on others.
He had to find you. Like a boat lost in the dark sea, Theo seeks for you as if you were his lighthouse.