Check out a first look image below as well as the promo featuring Sif following this past Tuesday's epsiode.
Marvel's Agents Of S.H.I.E.L.D. airs Tuesdays on ABC.
Coulson and team 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 MacK continue to hide their true mission from everyone close to them.