Animals seek rewards and the associated neural basis has been well studied. However, what happens when animals fail to get a reward is largely unknown, although this is a common result of behaviors such as predation. Fei et al. have established a model for investigating the effect of blocking an expected reward in Drosophila and provide a simplified framework for the underlying neural basis. The cover image illustrates the elevated octopamine level in a Drosophila larva that has failed to obtain a reward. See pages 901-911. (Cover image provided by Prof. Zhefeng Gong).