oh hey! If i understand right you’re trying to overlay an effect on top of a plane in front of the camera and still see stuff behind it right? you can do that by setting the plane in front of the camera to have a refraction material with an IOR of 1
and in the material settings make sure you have raytraced transmission turned on
then in your NPR tree plug combined color into the NPR output, anything you do in between that will be overlayed on top of the background render
