First SP of the so called "Moon Trilogy" by Kitagawa Eriko (followed by "Tsuki ni Iku Fune" and "Mittsu no Tsuki" - but don't worry, the three specials are only linked by the "Moon" in the title, by the rural setting, and by the same ML, Tanihara Shosuke), it proves once again what a fantastic screenwriter Kitagawa-sensei is!
It's a bit hard to explain why this SP is so good, without giving away any detail, but that'd be a real pity 'cause it'd rob you of the lovely experience of finding out by yourselves...so let's just say that it's a romantic but at the same time realistic tale, set in a beautiful rural scenery and graced by an extremely good performance by Tokiwa Takako and by some nice music on top of that.
(Of course, if your ideal of "romantic" story is something like "rich and arrogant CEO with a Ferrari + young and naive secretary with long eyelashes", you might disagree...)