Complex sentence: She takes the case and returns to her apartment, where she opens the painting and sees the portrait of Dracula--it is a portrait of Adam, and as she looks at the painting, it comes to life, and Adam grows fangs.
Split into simpler sentences: She takes the case and returns to her apartment, where she opens it and sees the portrait of Dracula--it is a portrait of Adam. As she looks at the picture, it comes to life, and Adam grows fangs.