Kuroshitsuji is my second most favorite anime. It's story is about a 12-year old English earl, Ciel Phantomhive, who contracted a demon to be his butler and named him Sebastian Michaelis(see this WORLD's wallpaper? It's them!:).
The anime has its origins from a manga of the same title by Yana Taboso, with the genre humor and supernatural. Most of the storyline was derived from there, but there were story arcs and characters from the manga that were excluded(i.e. the Noah's Circus arc, Joker and his gang) and replaced by equally impressive stories and characters(i.e. the purification of London by Ash, Fred Abberline).
The series has only one season, spanning 24 episodes, but at Sono Shitsuji, Shūshō: Saigo no Bansan o Anata to Tomo ni ( "That Butler, Last Chapter ~a last supper with you~") event on June 14, 2009, it was announced that there will be a second season. Yehey for Kuroshitsuji fans!
Now, on with the analysis! The series revolves around the daily life of Ciel and his household being managed by Sebastian. As the Queen's guard dog(someone who monitors the affairs in the London Underworld), Ciel is usually involved in investigations of gruesome cases that is usually caused by supernatural cases(i.e. "Jack the Ripper" case spearheaded by Madame Red and Grell Sutcliffe, a shinigami). Overall, the anime has a gothic feel, occasionally lightened by funny situations and the antics of the characters. The ambiguous relationship between Sebastian and Ciel is a plus too, attracting dozens of yaoi fans of the anime world(Kuroshitsuji is NOT yaoi, Hoping it's one though, minus the smut. I love the Sebby-chanxCiel-kun pairing!) I really recommend Episode 4. Watch, you'll know why!.
I also love Kuroshitsuji's soundtrack. The opening song, Monochrome no Kiss, is really apt for Sebastian's character(some say it's a proof that Kuroshitsuji has yaoi elements because the song is a love song) while its ending song is the lively I'm Alive of Becca, which is a personal favorite of mine, is the fitting song for Ciel. Lacrimosa, the concluding song in the later chapters, is the perfect song for the relationship between the demon and the young earl with its haunting notes.
As a lover of gothic, this anime with its unique mixture of darkness and humor passed my discerning palate with flying colours. Add to that the magnificence of its artwork(Sebby-chan smoking HOT, Ciel-kun KAWAII!), it really is an anime to be watched.
So what are you waiting for? Buy a dvd or watch Kuroshitsuji in any video-broadcasting web sites now. I assure you, you'll love it!