A video lesson with generative learning activities has the potential to improve learning by engaging learners. However, existing literature regarding designing and implementing an interactive video lesson is insufficient. In the present study, we aimed to investigate: a) whether the use of the summarizing strategy would benefit learning via video with regard to learning outcome, cognitive load, intrinsic motivation, and metacognition; and b) which self-explanation prompts would further engage learners. A total of 149 university students were randomly assigned to one of six conditions formed by a 2 x 3 design with self-explanation prompts (structured prompts vs. open-ended prompts) and summarizing (constructed summarizing vs. provided summarizing vs. no summarizing) as the between-subjects factors. Analysis of covariance indicated that: a) the structured prompts reduced extraneous cognitive load and fostered metacognition, b) the positive effect of the structured prompts on retention was dependent upon no summarizing, and c) the provided summarizing strategy resulted in higher perceived competence when compared to the constructed summarizing strategy. These findings are discussed within the contemporary engagement theory and cognitive load theory.