With their 2015 release, No Closer to Heaven, Philadelphia's the Wonder Years made a move away from the spry pop-punk of their early days to create something heavier and ultimately darker. This trend continues on the band's sixth album, Sister Cities, a worldly collection of songs developed from two years of tour journaling by frontman Dan Campbell. Ranging from warmly introspective alt-rock to full-throated emo, the band explores themes of distance, detachment, and interconnectedness: concepts they noted over and over during their global travels. From the grief-stricken longing of "Raining in Kyoto" to the travel-weary reflections of "We Look Like Lightning," the band delves deeply into the human experience of being away from home and the connections both made and missed. The overall tone of Sister Cities is intense and, at times, comes across as unrelentingly dour. Still, the Wonder Years' maturation from suburban pop punk ennui to (literal) world-weary emo desperation feels like a logical progression, and it's hard to fault them for tackling bigger subjects.