Nihongo Sou Matome N4 Audio Download Portable 〈PREMIUM • Edition〉

I should first verify the existence of such a series. Let me think. "Sou Matome" is sometimes translated as "All in One," and there are books like "Sou Matome Nihongo Kyoushitsu" by Japanese educators. The publisher might be a company like Asan Publishing or similar. If the series includes audio, they might have CDs or offer downloads.