Seven:
Amu
Ran
Miki
Su
Dia
Yoru
Aruto Tsukiyomi (Ikuto's father)
Seas:
Aruto Tsukiyomi, Ikuto's father, was Lost overseas.
Treasure:
Amu Hinamori is the treasure Ikuto has been searching for.
toi would mostly get touched if toi were an Amuto fan like me. But even if toi ship Tadamu ou other Amu/Ikuto related couples, toi could still get touched par Seven Seas Treasure's meaning.