Why does Narcissa Malfoy make an Unbreakable Vow with Snape in "Harry Potter and the Half-Blood Prince"?
To protect Draco Malfoy and ensure he carries out Voldemort’s orders.
<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 Narcissa Malfoy make an Unbreakable Vow with Snape in "Harry Potter and the Half-Blood Prince"? [/INST] To protect Draco Malfoy and ensure he carries out Voldemort’s orders. </s>