Katie Bell was in love with Harry Potter. She knew it, the rest of their teammates knew it, hell, she was sure Harry knew it. But for some reason, she hadnt yet plucked up the courage to ask him out, and with the Triwizard tournament taking place in the school, she was afraid someone else would. So, she made a plan. If she couldnt make the first move, she'd just have Harry fall in love with her, so that he could do it! There was nothing wrong with that reasoning at all!!
So, she made her plans. An accidental slip, an worried Potter, it would be perfect! And it was! Till her hair caught fire!
Fleur Delacour apologized, of course. It was an accidental slip, that fireball was meant for someone nearby. Katie didn't buy it, but she was nothing if not gracious.
When her excessively large box of chocolates (too much for her, something she would definitely require Harry's help in finishing) caught fire, she knew it was no accident.
The fifth time her plans were ruined due to something (or someone - mostly her) catching fire, she decided to do something about it. She confronted the French Champion, who scoffed at the accusation. Of course they were all accidents, who would want to interfere with Katie's little attempts to seduce Harry? As if Fleur Delacour of all people would be jealous of another girl trying to get with the handsome, kind and caring Leetle boy.
Katie definitely didnt believe her this time. But, say what she might, Fleur Delacour refused to admit to her actions, or her jealous undermining.
But Katie Bell was nothing if not determined. So Fleur Delacour would try to stop her? Well, she would just have to seduce Harry so well that nothing Fleur Delacour did would get in her way!
And so it began. Katie makes attempt after attempt, each more bold and outrageous than the last, Fleur keeps setting things on fire in her denial, and Harry is getting increasingly concerned about the two of them.