Tabitha is Agnes’s legal mother who dies when Agnes is young, apparently due to illness, though it’s later implied that her husband Commander Kyle murdered her. Although Agnes initially believes that Tabitha is her biological mother, she learns shortly after Tabitha’s death that Tabitha adopted Agnes after Agnes was retrieved from her true mother, an escaped Handmaid, and brought back to Gilead as a toddler. This is difficult news for Agnes to cope with, but even so, Agnes and Tabitha truly loved each other while Tabitha was alive.