He asks your sim to find his sacrophogus at the back of the oasis and take it to your suite. Once there, Horus comes out of the sacrophogus and then tells the player that someone robbed him of the Branding Iron. After asking Jeb about it, he admits to taking it from Horus's tomb and using it to free Honest Jackson from one of the jail cells since the key was lost as he had accidentally locked himself in one. Horus then interacts and uses the Manager's Suite as his own until the goals by him are completed.
His secret is he is running an on-line wrapping gift service.