Back in 2006, John Carney made his directorial debut with the Oscar-winning film "Once," a movie about the power of music and healing. Eight years later, Carney returns to the musical drama with "Begin Again," a strongly acted and earnest film that aims to be uplifting and entertaining.

The film tells the story of Dan (Mark Ruffalo), a washed up music executive who suddenly gets fired from his job. Meanwhile, Greta (Keira Knightley) gets dumped by her boyfriend Dave (Adam Levine) as he embarks on a music tour. When the two meet by a coincidence at bar, Dan and Greta form a friendly relationship that leads them to recording an album on the streets of New York City.

The major theme in the film is music as a means of art therapy. What is interesting is that all the main characters have been broken by music. Dave leaves Greta to pursue his music career and Dan has left his family to make money selling artists. Essentially, when music is brought in as a business and not as an art form, it loses its essence. Greta continuously says she writes music for fun but does not like to perform. As a result, when Greta and Dan decide to record their album outdoors, the calculated nature of albums gets lost and instead it becomes more a joyful and natural experience. It essentially serves as a connecting tool to bring Dan closer to his family and Greta to realize her potential; for Dave, it becomes a means to seek forgiveness.

Mark Ruffalo plays Dan to perfection. When he is arrogant, he becomes quickly self-destructive. At the beginning of the film, Dan is unable to accept changes that are happening in the music business and does not care to listen to his partner Saul (Yasiin Bey, a.k.a. Mos Def). He is disheveled and almost looks more like a homeless man than a successful executive. He frequently drinks and his interactions with his daughter Violet (Hailee Steinfeld) and his ex-wife Miriam (Catherine Keener) are artificial. In one scene, when his daughter asks how old she is, he is unable to respond correctly and even lets the issue go in a very nonchalant way. However, once he meets Greta, Dan begins to rethink his life. He begins to care about his attire, his interactions with his daughter and ex-wife begin to change, and he stops drinking. Ruffalo's subtle gestures and movements create a character that is easily charismatic and one that audiences can relate to.

Meanwhile, Keira Knightley's Greta begins as a weak and dependent character who grows into a strong self-sufficient woman. Knightley has become one of the most divisive actresses of our time due to her emphatic style and her period pieces. However, in this movie, she is extremely subtle. Knightley loses the glamour associated with her work in costume dramas and instead is seen throughout in jeans, flats and blouses. This makes her performance all the more credible. Some of her best moments are with James Corden, who plays her friend Steve. In one scene, Greta and Steve are talking about her ex, Dave, and while it is obvious Knightley's character is suffering from her break up, Knightley's use of improvisation moves the scene away from potential melodrama.

Knightley also impresses with her vocal skills. The actress showcases an angelic, soulful and magnetic voice from the moments she arrives on screen with the song "Step You Can't Take Back." Other songs she impresses in are "Lost Stars" and "Tell Me If You Wanna Go Home."

Hailee Steinfeld also gives a memorable performance as an angry teen in search of friends and more family connection. Meanwhile, Adam Levine impresses in his feature film debut as Dave. The singer brings his usual charm but also gives his character a vulnerability audiences have not seen in his TV work. He is particularly impressive in a scene where he tries to reconcile with Greta. Levine lets it all out in a most subtle way and it almost feels like watching a seasoned actor. It is also a pleasure to hear Levine's tenor/countertenor voice in the film's soundtrack.

Ceelo Green provides some comic timing while Catherine Keener brings her magnetic presence to the screen in the small but, crucial role of Dan's ex-wife.

The other strong element in the film is the music, written by Carney, Gregg Alexander, Danielle Brisebois and Nick Lashley. Each song has its own distinct melody and never falls into the trappings of mainstream music. The instrumentations blend smoothly with the violin, cello, bass and drums never interfering with the vocals. The songs also provide some unique and detailed lyrics, which during this day and age are hard to come across.

One of most memorable pieces is "Like a Fool," which Greta angrily sings to Dave on his voice mail. It one of the film's truly resonating songs and scenes.

Carney's editing and filmmaking style also keep the movie light, fresh, and swift. One of the most unique sequences in the film is the opening. Carney shows it three times from different perspectives. The beginning of the movie shows it from Knightley's as she takes the stage and sings her first song. Later, Carney cuts to Ruffalo's perspective and flashes back to how he arrived at the bar. The final time shows it from both of their perspectives. Essentially, it not only presents the two principals, but foreshadows how they will connect throughout the film.

The director also implements the use of various montages throughout. There is one tender montage in which Greta and Dan walk throughout New York City listening to music. The interactions between the two actors, the use of the music and the Manhattan landscape make it incredibly effective.

"Begin Again" will definitely not please all audiences, especially if you're looking for something unpredictable. However, it is a feel-good movie that feels genuine and one that will resonate with viewers in search of an uplifting journey.