The combo is to use Prophet Velen then Mirage Caller plus double Mind Blast for a 40 damage otk (after an Emperor Thaurissan obviously). If you need more damage you can use Radiant Elemental allowing for upwards to 88 damage (If you Shadow Visions two Mind Blasts).
I used to run Lyra in the deck but I think Gadgetzan Auctioneer is better since you would rather cycle through your deck to find the combo then get random spells.