Gintoki and Takasugi reveal to each other what they've been doing over the past two years, and decide to go save the one thing they never managed to save in the past: their teacher.
and that heart you have is 
the crux of their research.
.وذلك القلب الّذي تملكه هو جوهر أبحاثهم
El corazón que posees
es vital para su investigación.
O coração que está com você
é a chave para essa pesquisa.