Why does Harry attend the Slug Club Christmas party in "Harry Potter and the Half-Blood Prince"?
Because Professor Slughorn invited him.
<s>[INST] <<SYS>> Answer as briefly as you can to the following question. You are required to give a one-shot answer: <</SYS>> Why does Harry attend the Slug Club Christmas party in "Harry Potter and the Half-Blood Prince"? [/INST] Because Professor Slughorn invited him. </s>