If you copy a spell that was cast for its adventure cost, does the copy also have the adventure restrictions?

When you copy a spell that was cast as an Adventure, the copy is created directly on the stack as a copy of the instant or sorcery spell. A copy of a spell is not 'cast' in the normal sense — it is placed on the stack by the copy effect and bypasses all normal casting restrictions and costs (CR 706.10).

The adventure rule (CR 715.3) states that after an Adventure spell resolves, the card is exiled so its owner may later cast the permanent from exile. This exile-to-hand restriction applies to the original card that was cast as an Adventure, not to copies of the spell. Since the copy is not a card and will simply cease to exist after resolving or being countered, it never goes to exile and imposes no follow-up restrictions (CR 706.2).

Additionally, the copy resolves exactly like any other instant or sorcery — it has no memory of being cast as an Adventure and no rules text tying it to adventure behavior. Only the original card's physical journey through the zone-change rules matters for the exile-then-cast-permanent sequence.

Example: Your opponent casts Brazen Borrower's Adventure, Petty Theft. You copy it with Twincast. The copy resolves and returns a nonland permanent to its owner's hand, then simply ceases to exist. Your copy does not exile itself, and there is no window for any player to cast a creature from exile as a result of the copy. The original Petty Theft card, however, does go to exile and your opponent may later cast Brazen Borrower from there.

Relevant rules: CR 706.2 (copies are not cards), CR 706.10 (copies placed on stack), CR 715.3 (adventure exile replacement effect applies to the spell's resolution involving the actual card).