Text (FS+errata): 2/2. ; Flash. ; When ~this~ enters the battlefield, return target spell or permanent to its owner's hand. [Oracle 2009/07/08]
A spell returned to its owner's hand isn't countered, it is simply removed and will not resolve. [Future Sight FAQ 2007/05/01]
A copy of a spell that is returned will go to the hand then cease to exist. [Future Sight FAQ 2007/05/01]
If the spell was played using Flashback (see Rule 702.31), then its effect will supercede this one and the card will be removed from game. [Future Sight FAQ 2007/05/01]