The Kepler spacecraft has detected an unusual pattern of transits across the disk of a star 1,500 light years away. It's an F-type star, so slightly larger than the Sun. So far, astronomers have been unable to imagine a natural explanation. The spacecraft instruments check out.
Is there, therefore, an artificial explanation? Could a huge structure built by an advanced civilization be orbiting that star? SETI researchers have been called in to listen for possible radio signals coming from that star.