Footprints is a poem written by Ella H. Scharring-Hausen who based it off her dream, in which she walked in the sand with God.
The anime version of H20~Footprints in the Sand starts out with this poem and has a significant relation to the plot.
One night I dreamed I was walking
Along the beach with the Lord
Many scenes from my life flashed across the sky.
In each scene I noticed footprints in the sand
Sometimes there were two sets of footprints
Other times there was one set of footprints
This bothered me because I noticed that
During the low periods of my life when I was
Suffering from anguish, sorrow , or defeat
I could see only one set of footprints.
So I said to the Lord. "You promised me
Lord, that if I followed You,
You would walk with me always.
But I noticed that during the most trying periods
of my life there have only been
One set of prints in the sand.
"Why, when I have needed You most,
You have not been there for me?"
The Lord replied.
"The times when you have seen only one set of footprints
Is when I carried you."
The title itself is formed from this poem, the H20 made from the main characters, Hayami, Hirose and Otoha, while the "Footprints in the Sand" is a reference to this poem.
Hayami Kohinata and Takuma Hirose both narrate a version of this poem at the beginning of the first episode in the anime. The opening scenes depict a beautiful sunny blue sky and a beach with two sets of footprints in the sand, Hirose saying the first words "He walked with God" and he mentions how these footprints, were the footprints of their lives. The narration then switches to Hayami gettting beaten by two boys in a rainy marsh and she mentions that in times of desperation and unbearable pain, there were only one set of footprints, she continues narrating by saying how God was only there in happy times. Hirose ends this narration with "When I needed you most, why were you not there for me?"
The second time this poem is referenced in the anime is near the end of the last episode. It begins with Takuma Hirose narrating, again at the sunnny beach that is depicted in the first half of this poem. He repeats the last lines of the first reference to the poem, saying that God was there in times of happiness but when needed, he was not there. The narrator then switches to Otoha who then states that God had been there the whole time, when the man saw only one set of footprints, God was carrying him the whole way. It then switches back to Hirose who states in the perspective of this man in the poem "I'm grateful for everything, thank you."
Otoha can be a reference to God in the poem, as she often comes and goes while assisting Takuma Hirose.