Target vs flipped face down

[true owl]

If player A targets a monster with infinite impermanence and then player B book of moons that monster the activated monster will resolve

My question is it something like fenrir targets a monster then said monster gets book of mooned, will the card still be banished face down or will fenrir resolve without effect?

[spark pulsar]

Nope, this only works because Imperm only negates effects while face-up on the field