Collaborative problem-solving (CPS) includes multiple socio-cognitive processes that can be challenging to investigate. Constructing arguments is a key practice at the intersection of CPS and science learning. To understand how students construct arguments and develop science knowledge during CPS, we focus on team synchrony--the extent of similarity of navigation actions between team members--in a game-based learning environment. Specifically, we examined the impact of team synchrony on students' argument construction and science knowledge acquisition in a science learning game, "Alien Rescue." Using a mixed methods approach, we analyzed a range of in-game data and performance data of 69 teams from 146 sixth-grade students. Our results show that team synchrony enhanced students' science knowledge acquisition, whereas its effects on argumentation features were nuanced: (a) higher team synchrony groups were more productive in constructing backing compared to low team synchrony groups in conditions where their prior knowledge was high, and (b) there was no significant difference between the two groups in generating claims. We also identified two illustrative cases to show the observed relationship between team synchrony and complexity of arguments that students constructed as a team. Our study has implications for tracing learning processes through log and textual data to understand students' CPS process and performance, which consequently inform the design of scaffolds that support students' CPS.