There are certain details about things that took place before the series started that are established but left unexplained. However, it's not too hard to conclude what the possible explanation would be. I won't go further into this so as to not spoil what little information is given in the series.
The characters are well balanced; there are cheerful ones, a quiet one, the resident oddball and even the strangely cute "mascot" of an unknown species. Most people are likely to find at least one character they like.
Despite its episodic nature, the show does carry one mystery that extends itself thought the series, though it is only elaborated on in a few episodes and finally revealed at the end.
The series has a few surprises now and then, however after a few episodes the mysteries presented on each episode become very easy to predict once you get used to the style, but they can still be amusing. This is fixed with several surprising plot twists at the end that manage to give the series a nice somewhat bittersweet ending.
If you like supernatural mysteries with a side of humor and friendship you'll like this series. Just don't expect a lot of romance because it's not a main theme. My only real critique is its episodic style and lack of closure; the current things are resolved, yet there's an important thing left in a cliffhanger, but it's still worth watching.
