The challenge in serious games is to improve the effectiveness of learning by stimulating relevant cognitive processes. In this paper, we investigate the potential of surprise in two experiments with prevocational students in the domain of proportional reasoning. Surprise involves an emotional reaction, but it also serves a cognitive goal as it directs attention to explain why the surprise occurred and can play a key role in learning. In our experiments, surprises were triggered by a surprising event, ie, a nonplaying character who suddenly appeared and changed characteristics of a problem. In Experiment 1--comparing a surprise condition with a control condition--we found no overall differences, but the results suggested that surprise may be beneficial for higher level students. In Experiment 2, we combined Expectancy strength (Strong vs. Weak) with Surprise (Present vs. Absent) using higher level students. We found a marginal overall effect of surprising events on learning indicating that students who experienced surprises learned more than students who were not exposed to these surprises but we found a stronger effect of surprise when we included existing proportional reasoning skill as factor. These results provide some evidence that a narrative technique as surprise can be used in game-based learning for the purpose of learning.