This research investigates students' learning about the electron transport chain (ETC) process in photosynthesis by watching a video followed by playing a serious board game--"Electron Chute"--that models ETC. The learning objectives targeted enriching a mental model that students could use to explain the causal relationship of the ETC common misconceptions students hold. Eighth graders (N = 120) participated in a one-day activity using a video and game designed by the researchers to model ETC. This model explained how sunlight energy was converted into ATP involving a flow of electrons. A quasi-experimental design involved a pre-test/post-test essay where students from the two treatments--video only and video+game--were asked to interpret a diagram about ETC. Playing "Electron Chute" after watching the video was effective on addressing misconceptions about sunlight absorption by chlorophylls, oxygen, ATP and NADPH production and the electron flow during ETC. A survey collected data about students' experiences after the video+game treatment. The majority of students agreed that playing the game increased their ability to explain how plants use light energy. This study demonstrates a principled approach for designing a video and game to support students' ability to make sense of how complex systems work.