The relationship between music, sound, space, and time plays a crucial role in attempts to define the concept of “immersion” in video games. Isabella van Elferen’s ALI (affect-literacy-interaction) model for video game musical immersion offers one of the most integrated approaches to reading connections between sonic cues and the “magic circle” of gameplay. There are challenges, however, in systematically applying this primarily event-focused model to particular aspects of the “open-world” genre. Most notable is the dampening of narrative and ludic restrictions afforded by more intricately layered textual elements, alongside open-ended in-game environments that allow for instances of more nonlinear, exploratory gameplay. This article addresses these challenges through synthesizing the ALI model with more spatially focused elements of Gordon Calleja’s player involvement model, exploring sonic immersion in greater depth via the notion of spatiotemporal involvement. This presents a theoretical framework that broadens analysis beyond a simple focus on the immediate narrative or ludic sequence. Ubisoft’s open-world action-adventure franchise Assassin’s Creed is a particularly useful case study for the application of this concept. This is primarily because of its characteristic focus on blending elements of the historical game and the open-world game through its use of real-world history and geography. Together, the series’s various diegetic and nondiegetic sonic elements invite variable degrees of participation in “historical experiences of virtual space.” The outcome of this research intends to put such intermingled expressions of space, place, and time at the forefront of a ludomusicological approach to immersion in the open-world genre.