Guided by the Sun - System Reference Document

From the introduction:

In Guided by the Sun games, 3-6 players tell the journey of a protagonist on a mission. It is played over a series of “turns", where the protagonist faces a challenge/adversary with a new ally they meet along the way. Depending on what cards are being played, the ally may join the protagonist on their journey. At the end of the journey, cards are played to determine the outcome of the protagonist’s mission. The more friends they have made along the way, the more likely they are to succeed.