瓦礫 means “rubble” or “debris,” usually referring to the remains of something broken or destroyed. It is a vivid and less common word that creates a striking image in the lyric 「瓦礫に咲く花」, meaning “a flower blooming among the rubble.”
The phrase symbolizes finding hope and strength even in difficult circumstances, making this word both memorable and central to the song’s message.
Janne Da Arc sing to someone still hurting after a breakup they never saw coming ("「まさか」の別れから" [since that "no way" goodbye]). They have grown timid, run from lonely nights and tried to lose themselves in the city. The song's sharpest line pins down what the loneliness really is: "一人が淋しいわけじゃなくて / 一人と思う事が淋しい" [it isn't being alone that's lonely / it's thinking you're alone].
From there the singer turns the hurt into a reason to move. Their days are "世界に1つの物語" [a story unlike any other in the world], and grief that won't fade will one day become "逃げない強さ" [the strength not to run]. The chorus is the invitation in the title: "旅立とう 地図にない場所へ" [let's set out for a place that isn't on any map]. Leave the extra baggage behind today, look up at the sun like "瓦礫に咲く花" [a flower blooming in rubble], and trust that once the rain you hate has stopped, you can start walking again.