Julie Tepperman and Mitchell Cushman, co-creators, playwrights, and directors of Brantwood, write about the process of creating the largest site-specific immersive musical in Canada. Originally commissioned by Associate Dean Michael Rubinoff and Sheridan College’s Musical Theatre Program, Brantwood was designed for and performed in a 90-year-old school in Oakville, Ontario that had been closed down due to low enrolment. The piece consisted of 40 original songs (composed by Anika Johnson, Britta Johnson, and Bram Gielen) imbedded in 11 one-hour scripted storylines, each set during a different decade in the history of this imaginary high school. The 15 hours of total material unfolded simultaneously over the course of each three-hour performance, and the audience had free rein to roam everywhere in the building and to follow whichever character they chose in the 42 person cast. Julie and Mitchell write about the challenges of creating theatre on such a large scale, and immersing the audience in an environment that gives them freedom to roam and explore, and engage with the show in both direct and indirect ways, and to push the boundaries of intimacy between performer and audience.