In Tale of Two Cities by Charles Dickens, the character of Lucie Manette is not very delevoped.  She is the typical Victorian heroine, swooning when overcome,frail and delicate, always in need of a man to protect her. In Book the Second, Lucie is the "golden thread" that holds others together, the carnation of concern and compassion.  Since Lucie's name is derived from the word light, Lucie represents the light that guides, and those who come into her light are guided and often illuminated themselves. In some ways she is like the "fair maiden" who inspires the knight to commit noble deeds. For instance, it is Lucie who inspires Carton to redeem himself through his self-sacrifice.  enotes best describes her,

Lucie is a catalyst; she does not change anything herself; but she is the cause of change in others.

As such a catayst, Lucie plays her role in the Revolution.  For the most part, however, Lucie is passive, although she acts as a prophetress when she hears the "Hundreds of Footsteps," that portend the Revolution.