Premieres December 31, 2024. The new PV is here. Check out the ANN article for additional information. Synopsis from AniList:
In a Holy Grail War, Mages (Masters) and their Heroic Spirits (Servants) fight for the control of the Holy Grail—an omnipotent wish-granting device said to fulfill any desire. Years have passed since the end of the Fifth Holy Grail War in Japan. Now, signs portend the emergence of a new Holy Grail in the western American city of Snowfield. Sure enough, Masters and Servants begin to gather…
A missing Servant class…
Impossible Servant summonings…
A nation shrouded in secrecy…
And a city created as a battleground.
In the face of such irregularities, the Holy Grail War is twisted and driven into the depth of madness. Let the curtain rise on a masquerade of humans and heroes, made to dance upon the stage of a false Holy Grail. This is a Holy Grail War covered in lies.
Fate/Zero is the best place to start in my opinion. And a fantastic show.
Edit: And if you wanted to watch it from “the beginning” you could try Fate/Stay Night UBW, but Fate/Zero is a prequel to that (and better).