ツキis the moon, ゴモリ is hidden. Therefore, one possibility is the moon was covered with clouds. The other possibility is that the moon changed its shape into dark of the moon. Since the term is old grammar, I don't know exact mean.

Big thank you. And can you tell me what means ツキゴモリ?

It is very interesting that you are trying to translate lyrics of Vocaloid song. I hope you will make it more popular in future. I don't have a sense of poem or writing lyrics in English, so I just describe the meaning. Therefore, you have to change it in more poetic English if you want to make subtitle. 歌詞Lyrics 夜の空に呑み込まれそうな Night sky is banking over 遠い星のささやかな体温 modest body temperature of a distant star 仄（ほの）か光る小さなライト 足元だけ照らしている faint and small light shines light on only foot 真夜中の迷路　深く深くに 迷い込んだままで 僕は一歩先でさえおぼつかない闇を駆け抜けた I run through darkness which is hard to see walk, still getting lost in deep, deep labyrinth in midnight. そこにありますか　僕の道は Is there my road? 月が消えたその夜に僕を呼ぶ声がした I felt someone called at the night when moon disappeared. 止まらず　ここまでおいでと誘う It is contiunually attracting me to come there. ずっと走り続けてる　君がいる場所へ こんな月のない　暗い空の下でもI keep running to your place even though under such a dark sky without moon. 指の先で星を結んで I tied stars with fingers 自分だけの神話を描いたの and portrayed a myth tail. 粒のような　小さな願い a tiny wish like a sand 僕の空を照らしている is illuminating my sky. どこかに隠れた　月を探して Looking for a moon hidden in somewhere, 立ち止まるのはもうやめた I stopped stopping. どれだけ視界が　閉ざされてても変わらない However closed my vision, it doesn't change 目指す場所はもう知ってる　そう where I should go, and I know it. 今もずっと聴こえてる　君の澄んだ声が I can still hear your clear voice, もうすぐここまで来るよと微笑（わら）"I am coming" with your smile. ずっと走り続けてる　君がいる場所へこんな月のない　暗い空の下でも I keep running to your place even though under such a dark sky without moon. 誰もいないこの場所で　頬を伝う涙 The tears fell down my cheeks here, and nobody is around. 独りでいたい　いたくない I want to be alone, and don't want to be alone. ずっとずっと聴こえてる　掠（かす）れたその声が I can still hear the slightly horse wisper, 早く私を見つけてと叫ぶ "Find me soon" ずっと走り続けてる　君に会いたくて I keep running to see you. 今は何もない　月隠（つきごも）りの空でも under such a plain sky with a moon banked over.