Zettai Kareshi or Absolute Boyfriend is a is one those unusual love story. Having a robot boyfriend is really weird. Even though it's kind of pathetic and absurd, Night is a passionate guy in actuality. Not to mention the looks and exceptional abilities, he tried his best to show his 'love' for riiko. Even though he is programmed to do such things, he exceeded his limitations as a robot and did sweet thing for riiko that every guy should really look up to. All in all, it is actually nice. The ending really made me want to cry. It is one of those must see series. Although i first saw it in my source as manga.
Source:
http://japanmangatoday.blogspot.com/2009/07/absolute-boyfriend-or-zettai-kareshi-is.html
** if you want the full synopsis, you can visit the link.