Last week, we showed you both a new poster and a video that touts the return of Jaimie Alexander's Lady Sif on this week's episode of Marvel's Agents of S.H.I.E.L.D. titled "Who You Really Are". Before the new episode debuts tonight on ABC, the network has released yet another poster featuring Lady Sif brandishing a sword and the tagline "Old Allies Return." Unfortunately for the Marvel's Agents of S.H.I.E.L.D., Sif may not be much help to them.

Tonight's episode centers on Coulson and his team as they come to the aid of a confused Lady Sif, who has lost her memory after fighting with a mysterious warrior, whose true mission will send shockwaves through S.H.I.E.L.D. Meanwhile, Bobbi and Mac continue to hide their true mission from everyone close to them. When Lady Sif last appeared on the show, she shed some light on the...