This essay takes initial steps on a journey with an Irish eco-spiritual philosopher, the late John Moriarty. As a gateway into his broader oeuvre and way of thinking, we explore Moriarty’s image of the Christian mystical Easter journey—the Triduum Sacrum—as a vision for humanity and the planet. After briefly reviewing his spiritual biography, we consider Moriarty’s re-framing of the story as a journey to the bottom of a symbolic Grand Canyon, a mystical trail beyond historical time to a primordial unity before the evolution of the species. There, the total integration of the natural ecumene is experienced. For Moriarty, this journey leads not only into the past, but prefigures a pilgrimage that everyone can—and should—take. Analyzing primarily his own writing, we highlight the intercultural roots and ecumenical connections of Moriarty’s work, which draws extensively on spiritual traditions and contemporary debates from across the world. On that basis, we sign-post directions for further research into a potential post-Christian ecology as a new way of thinking about the earth and our role on it, based on an attitude of Gelassenheit.