Promises, the latest album from indie rockers The Boxer Rebellion, proves that you can give your fans what they want and still surprise them over the course of an album. How does the London-based band do it? It's quite simple, really: It starts with the hook-filled, radio-ready synth rock single "Diamonds," then follows it up with breathtaking, ethereal guitars and lush soundscapes on the otherworldly "Fragile." Having shown its range, the band spends the next four songs or so giving listeners more of what it delivered in the first two tracks — daring fans to think that too much of a good thing is actually bad — before the primal percussion and raw energy of "New York" takes the second half of the album in a new direction. Singer Nathan Nicholson sounds a lot like Anberlin's Stephen Christian on the emotional rocker "Safe House," and by the time you get to the heavenly rock 'n' roll of "Dream" or the almost operatic closer and title track, you can hardly believe this is the same band. The reason all this musical evolution works so well: The progression feels completely organic and necessary.