Forum:Light of intervension question

If "light of intevenstion" is face-up on the field you can no longer normal set, when you do normal set it is normal summoned in face-up defense. "Slifer the sky dragon" as the effect of cannot be normal set, then why if "light of intervesntion" is face-up on the field "Slifer the sky dragon" cannot be normal summoned in face-up defense?96.44.92.186 (talk) 21:59, May 29, 2013 (UTC)