Hera's plan was to lure Aphrodite into submission

and send her to where Hephaestus lay while simultaneously

sending Athena out into the forest.

A siren's lullaby was all it took, and off Aphrodite went.

She cast a spell of intoxication on Hephaestus while she commanded Aphrodite to seduce her son.

She wanted Athena to be as far away from Hephaestus before the latter wakes up so Aphrodite

can get there in time which she successfully did. 
After all, she was so powerful she had the command over the skies and could either bless Simanity
with clear skies or curse them with storms. 
She then brought forth rain and dark skies as she chanted aloud the words
that would soon send Athena to the forest. 

Athena wandered around aimlessly in the rain while in a trance,

no longer in control of her own body.

Hera commanded her to head straight to the river

where she disappeared like the bright moon that faded behind dark clouds.