She embarked a ______quest to decipher the cryptic symbols etched the _____ancient artifact, unraveling its hidden secrets.

She embarked a __quest to decipher the cryptic symbols etched the _ancient artifact, unraveling its hidden secrets.

upon; beneath

towards; amidst

onto; through

about; within

"She embarked upon a quest to decipher the cryptic symbols etched beneath the ancient artifact, unraveling its hidden secrets."

Upon is used to indicate the beginning of a journey or quest.
Beneath refers to the location or position of the cryptic symbols on the artifact.