Let \( Q \) be the mirror image of the point \( P(1,0,1) \) with respect to the plane \( S:x+y+z=5 \). If a line \( L \) passing through \( (1,-1,-1) \), parallel to the line \( PQ \) meets the plane \( S \) at \( R \), then \( QR^{2} \) is equal to:
