Concept makes or breaks Swiss metal band EMERALD's latest album, "Restless Souls." In places, the band's sixth studio album shines, but in others, the concept and ambiance is either too out there or too weak to make it a unified masterpiece. The album starts strong. The first track, "Freak Show" begins with haunting ambiance. Then, it goes into a classic power metal opener. The concept was what hooked me to the album; the combination of lyrics welcoming the listener to a fictitious freak show and the carnival ambiance the instrumentals created made it an interesting listen.

The ambiance and the conceptual lyrics are what either make or break the tracks on the album. The second song is solid, but the lyrics and ambiance were nothing to write home about. It has some good licks, but it doesn't stand out to me as anything different than what I've heard for the last several weeks of reviewing albums. Same with "Digital Slavery," the third track, and the sixth track, "The Wicked Force." However, the latter had better thematic elements and was a solid song. "Son of Sam" was a stand-out for me. With the classic atmosphere and good thrash elements in the chorus, the instrumentals fit well and highlighted the lyrics thematically. The powerful melodies are strong, but the concept, again, is what makes this song. "Final Stand" also had a good, classic atmosphere and good thrash elements in the chorus, but it was more of a stand-out instrumentally.

"Cad Goddeau" and the title track, "Restless Souls," were also stand-outs. The most symphonic tracks on the album, both had the lyrical and instrumental ambiance to keep me hooked. Unfortunately, the next two songs were less pleasing to me. "Set me Free" had nothing noteworthy in it except for a slower tempo, and "Superhero" didn't have the same pull as previous, stronger thematic songs. "Heaven Falls Down" and the final bonus track "Revenge" had solid thrash elements and added some variety to a consistently mid-tempo album where the songs were all in 4/4-time.

Overall, the album is hit or miss. When the thematic elements, lyrics, instrumentals, and ambient sound, work together and have some uniqueness, the songs are great. When the instrumentals start out like every other mid-tempo power metal band without the ambiance or concept to take it to the next level, the album falls flat.