For album number five, Las Vegas quartet Imagine Dragons recruited executive producer Rick Rubin and dug deep into the emotional well with Mercury: Act 1. While containing just enough of their typical hallmarks -- booming percussion, emotive delivery, and the ability to command full attention with their in-your-face approach -- to make this an unmistakable Imagine Dragons record, the Dan Reynolds-led group takes a big risk on their grandest bid yet for maturity and authenticity. The results come close enough to the mark, showcasing some of the most soul-baring and cathartic moments of their careers. Unlike the bulk of the music for which the band is known, there aren't any arena-sized neo-Jock Jams or immediate radio hits present on the album (the tender, lovelorn ode "Follow You" and gleeful kiss-off anthem "No Time for Toxic People" are as close as it gets). Dealing with mental health, death, and fractured relationships, Mercury pushes the listener to process pain and inner turmoil, embracing the darkness to find hope and acceptance. To achieve that cathartic release, Reynolds delivers his most intense performances to date, pushing his vocals to the breaking point on several occasions ("Giants," "Dull Knives," and "Cutthroat" are almost painful to listen to, purely because fans might wonder if he actually burst a vocal cord during recording) and dropping his guard to reveal uncomfortably vulnerable confessions (the devastating "Wrecked" is a beautiful standout, written about his late sister-in-law). Despite the seriousness, the band balances the set with some relatively upbeat tracks that at least resemble "classic" Imagine Dragons, like the bouncy plea to the heavens "Lonely," the synthy Muse-like "Monday," and the sparkling "Easy Come Easy Go," which offer much-needed breaks from the intensity. On the affirmative "It's OK," Reynolds sings, "It's OK to be not OK/It's just fine to be out of your mind" before beseeching, "Just let me live my truth." This is the essence of the entire album. No matter how ugly and tough life can be, some acceptance and resignation can go a long way toward healing and happiness. For a band that usually goes overboard with hyperbolic, repetitive slogans (whether it's "Feel the thunder!" and "Whatever it takes!" or "Radioactive, radioactive!"), it's refreshing to hear them push themselves into such unpleasant yet absolutely human corners. While the overall tone and narrative could use a little polishing, Mercury: Act 1 is a huge step forward in their maturation process. ~ Neil Z. Yeung