Hidden Temples of Necrovalley is a Continuous Spell Card.
Spell Cards are usually activated from the hand on your turn unless their type gives another timing window.
On the current TCG and OCG Forbidden & Limited lists tracked here, Hidden Temples of Necrovalley is Unlimited.
YGOPRODeck lists Hidden Temples of Necrovalley for these formats: Speed Duel, Duel Links, Common Charity, TCG, OCG, Master Duel.
Hidden Temples of Necrovalley belongs to the Gravekeeper's archetype—use that tag when searching for engine pieces and tech options.
A listed print of Hidden Temples of Necrovalley appears in 2014 Mega-Tin Mega Pack (MP14-EN230) at Rare rarity.
Among markets shown on this page, the lowest listed snapshot for Hidden Temples of Necrovalley is about $0.14 on Cardmarket (prices change frequently).
