This is the same quest that starts the aging process, the life dreams quest. You will have the option to assign a life dream to your sim and create an orb. The orbs start at bronze and then as each sim ages and dies you assign the orb to the next sim to create a silver orb, and so on through gold and then finally to platuim. When I did this I created mule sims just to get through the orbs. You can also use the orbs to build things like the beach, the animal park, etc. the web site
www.girlwhogames.com has a lot of information on this and other quests.