Before they recorded the album ". . .And Justice For All", they took then-new bassist Jason Newsted into a studio to record an EP called "The $5.98 E.P.: Garage Days Re-Revisited".
"Helpless" was originally recorded by Diamond Head. There are a lot of fan favorites in this Garage album as well as "Garage Inc.", which folded in previous "Garage" covers and a whole new album of covers. At their best, Metallica's cover versions of songs just bring out the best in the original while keeping true to their roots.
Here's a bluesy version of the tune they recorded for some kind of special on MTV.