When the anomaly appeared at the Earth's core, the Substratum Protocol was initiated. You are the best and brightest scientists we have left, our last hope to stem the apocalypse. You are the Substratum Expedition Team. Descend. Learn. Survive. A solo+ survival mystery RPG using step-down dice and card draw mechanics, Substratum Protocol is playable as both a solo game or guided by a GM for 2–6 players. With players taking on the role of Earth's best remaining scientists, Substratum Protocol is our entry into the Deep Delving Mystery genre (like Subnautica and In Other Waters). On their grueling journey to the center of the Earth, members of the Substratum Expedition will overcome challenges, gain clues and knowledge of the anomaly, discover creatures, aliens, cosmic horrors, and ultimately assemble their final hypothesis to overcome the apocalypse looming before them. 88pg, A5 sized, hardback, full color