They need the jewels to solve the puzzle that Thoth left for those who want to find his temple and get his advise on something (valuable cause Thoth's god of wisdom and knowledge, and he also makes propechies). Seth and Horus want to find Thoth's temple so they can ask Thoth if what happened to Seth and Horus' own premonitions about "the end of the gods" have something to do with Thoth's old propechy that "two children of Nut will change Egypt". That's the reason that Seth and Horus are going. Foreign god, however, has his own contract thing going on: he won't invade Egypt in exchange for Thoth's using his wisdom and divination to give him helpful info and advise on some problem that he has back home, and which he hasn't revealed yet (and Seth wants to keep an eye on FG so he keeps his end of the deal).
thenks JAYYYYY
can somebody liek, explain the plot again??? Liek...what were they doing w the jewels again?