Activate Ancient Den by tapping it, adding ({W} magic symbol) .
Activate Mind over Matter by discarding Seat of the Synod, untapping Ancient Den.
Activate Ancient Den by tapping it, adding ({W} magic symbol) .
Activate Tameshi by paying ({W} magic symbol) and returning Ancient Den from the battlefield to your hand, returning Seat of the Synod from your graveyard to the battlefield.
Activate Mind over Matter by discarding Ancient Den, untapping any applicable permanent.
Activate Tameshi by paying ({W} magic symbol) and returning Seat of the Synod from the battlefield to your hand, returning Ancient Den from your graveyard to the battlefield.