Dandelion Garden is an orphanage near to Tenchi Academy, the one that took in Kurogane Hayate and Nagi when they were babies. It is owned and run by a woman named Chiharu, and there are maybe a dozen young children living there. The environment is very much like that of a regular home, and all of the kids are happy there.
Unfortunately, the orphanage is in debt with the Smiley Finance loan company, and Chiharu is having lots of trouble paying off her debts. At one point, the orphanage is vandalized when Chiharu is late on her payments. It is this predicament that kickstarts Hayate's adventures in Tenchi Academy as she tries to earn the money to save her second home.
Since Hayate has begun earning money for the orphanage, it has fared much better, and comes closer and closer every day to being out of debt. Hayate visits the place often to play with the kids and have fun, oftentimes dragging Ayana along with her.