Speak to Mostrasz at the Vermillion Redoubt and fly to Ravenholdt Manor together.
If the egg is in Ravenholdt Manor, we can't risk torching it in an all-out assault. I'll need someone slippery to get in there and find out for sure.
That's you, <name>.
Mostrasz will help you infiltrate the compound. Speak to him just outside and fly to Ravenholdt together. Good luck!