Sif happens! Those badass investigators on Marvel's Agents of S.H.I.E.L.D. will soon meet their match when attacked by Lorelei (Elena Satine), a deadly, flame-tressed vixen from the Thor comics. But, never fear, Lady Sif is here! Actress Jaimie Alexander, who played the bodacious warrior-goddess in the movies Thor and Thor: The Dark World, will reprise her role on the ABC series as Sif tries to save the S.H.I.E.L.D. team. The episode, titled "Yes Men," is scheduled to air March 11.