After your parents were turned into pigs in this strange spirit world, you set out to save them. You got a job at Yubaba's bath house. But now, Haku is hurt. Terribly hurt.
Haku has 2 forms: seemingly human and a dragon. In his dragon form, he returned to Yubaba's bathhouse. He was terribly bloodied up and injured. You decided to go back to Yubaba's office to check on him before he bled to death.
You scrambled to get there as No-Face had become some sort of man-eating monster. When you rejected his proposal of gold, he became... enraged?
Finally, you got to Yubaba's office. Haku was there on the edge of the carpet, next to some sort of hole, which was probably the top of a chimney or something. There's a problem.
Yubaba's sister, Zeniba, had come into the office to get her magical golden seal back. Haku had stolen it for the magic secrets or something. She didn't care that he was dying, really. Eventually, three green heads pushed Haku into the hole, and since you were clinging to him, you fell with him.
Now, cut to the present. You had fallen into Kamaji's boiler room, where magic soot balls put coal into the incinerator. You were desperate to save Haku, who had by now turned back human once you fed him medicine from a river spirit. But he was still passed out, bruised, bloody. You told Kamaji that maybe you could bring the golden seal to Zeniba and apologize to her for Haku. So you requested he tell you where Zeniba lives. He seemed surprised.
Kamaji: "You'd do that? Well, you could, but Zeniba is extremely dangerous!"