The Gu Family had a tragedy, the old lady of the Gu Family was bringing her daughter-in-law to see the doctor when they were hit by a startled old horse. Several people, along with the carriage, all tumbled into a ravine.
The old horse, the middle-aged man driving the carriage, and the old lady of the Gu Family all died. The sole surviving daughter-in-law of the Gu Family was so shocked and traumatized that she became somewhat delirious, continuously muttering, "It's my fault that Grandma died, Grandma died so horribly trying to protect me," and insisting on being buried with the old lady.
This was ridiculous, only members of the Imperial Family had to be buried with the deceased, and besides, she was pregnant with a child.
The Gu Family thought she had been scared out of her wits, and that she had only survived because the old lady had protected her. The shock was too much, causing her temporary irrational thoughts.