The Expanse (I)

A probe from an unknown alien source unleashes a devastating assault upon Earth. Enterprise is recalled, and along the way home Captain Archer acquires information that the perpetrators come from a region of space known as the Delphic Expanse - a place where very bizarre things happen, and from which few ships that enter ever return. Starfleet must now decide whether to risk sending the NX-01 into the Delphic Expanse to prevent a possible second attack.