Years before Agent Phil Coulson and his S.H.I.E.L.D. team swore to protect those who cannot protect themselves from threats they cannot conceive, there was Agent Peggy Carter, who pledged the same oath but lived in a different time, when women weren't recognized as being as smart or as tough as their male counterparts. But no one should ever underestimate Peggy.

The film takes place one year after the events of Captain America: The First Avenger, in which Agent Carter, a member of the Strategic Scientific Reserve, is in search of the mysterious Zodiac.

Benny and Claire, a down-on-their-luck couple, find a discarded Chitauri weapon referred to as 'Item 47'.