Rule 435.4

When a card Detaches from a Top-Most Card, its location is the same as the Top-Most Card from which it Detached.

• 435.4.a If the Detached card was a Gear and this causes it to become present at a Battlefield, it will be Recalled during the…
• 435.4.b If the Attached card was Detached because the Top-Most Card changed zones from a board zone to a non-board zone, then…

Official Core Rules