ABC's Castle returns to much audience delight

Three months after the season three finale of Castle left its viewers with a nail-biting finale, the crime fighting series is back with a bang.

Questions left unanswered: Would Beckett survive? Would the new captain at the precinct support Castle and Beckett's unorthodox pwwartnership? And most importantly, would Beckett remember what Castle said to her when she was dying?

For those who are not caught up: Richard Castle is a famous novelist who uses his connections with the mayor to follow Detective Kate Beckett around out in the field. His knowledge of crime and the criminal mind prove useful to Beckett and the other two detectives on her team, Javier Esposito (Jon Huertas) and Kevin Ryan (Seamus Dever), as they investigate everything from Mayan curses to magic shops.

The season four premiere begins with Beckett being rushed to the hospital, where her boyfriend must perform emergency surgery to save her life. Then we jump two months into the future, with Beckett going back to work, facing reality and dealing with the new captain. She has not spoken to or seen Castle since before the summer (they really have a bad track record with summers) and understandably, he is not very happy with that.

Add to the mix a captain everyone calls Victoria "Iron" Gates, who has kicked Castle out of the prescient and has halted investigations into Beckett's shooting because there are no new leads, and you get a recipe for fast-paced drama.

Fillion and Katic still have the same explosive chemistry they had. In fact, it has gotten better every season, and they clearly are able to play off each other in every scene and make it seem real. Katic herself really keeps the tension high in this episode, from her PTSD to her breakdown mid-episode. Huertas and Dever have some of the most humorous moments and keep things from becoming too dark. Even Alexis (Molly Quinn), Castle's daughter, has gotten more depth. She confronts Castle about what his police work might mean for his own health and that of his family, forcing him to face some truths about his actions.

So now there are two giant secrets: Castle is keeping the phone call from the mysterious man a secret from Beckett, and Beckett is not telling Castle that she remembers what happened when she was shot.

It's no surprise that both of these are going to come out into the open, and one can only imagine the characters' reactions when that happens.

Castle is definitely setting a different tone than it had been when it first started airing. It's a lot darker and a lot more serious, but the humor and the spark that makes the show Castle is still there. Showrunner Andrew Marlowe seems to know how to mix comedy and drama perfectly to keep the audience on their toes without giving them heart attacks, and it is that balance that keeps everyone watching.

Castle and Beckett are still the witty crime-fighting team that they were in season one.

It's just that the stakes are higher now. Castle knows that, Beckett knows that and the audience definitely knows that.

Just like title character Richard Castle, the show has grown up a little in the past three years, but it remains the same show the established audience loves and know -- just with a little more maturity and a lot more depth.