Forum:Geartown Q

If my opponent set geartown then he set a new facedown field spell can he summon a ancient gear? My opponent says it works because of this ruling "If you control "Geartown" and you activate a new Field Spell Card, you cannot activate "Geartown's" effect when it is destroyed because it misses the timing. However, if you Set a new Field Spell Card, you can activate "Geartown's" effect when it is destroyed." He says set new field spell is destroy so he get the eff. I said no which is right?