Solace House by Will Maclean

Summer, 1993, and Alex Lane finds himself at the end of the University summer term, broke and without any concrete plans. So, when he's offered the chance to join a group of students tasked clearing out Solace House, a large Victorian residence left to the University by a reclusive hoarder called Flayne, he jumps at it. The other students are a mixed bunch, but Alex quickly falls into a close friendship with the mercurial, red-headed Ella.

At first the house seems to be an ordinary, if grandiose, property. But as the team begin sorting through piles of junk, they stumble upon Flayne's journals in which he details his obsession with his missing mother, his discovery of a strange place called Bewise, and - most mysteriously - his belief in another realm lying parallel to ours, along with coded instructions on how it might be reached.

As the students continue to sort through the detritus, one of Alex's companions becomes increasingly obsessed with the hidden secrets of Solace House, Flayne's missing mother, and the possibility that, if only they can decipher Flayne's increasingly unintelligible writings, they might gain knowledge beyond their wildest dreams. That is, assuming, they are willing to sacrifice everything.