How do you get the scientist to lead you down to his laboratory so you can see the Mermaid in Harvest Moon DS?

Answer 1

easy. all you have to do is get daryl's (daryl's the scientist, for those readers that don't know) friendship points above 100.

you can see friendship points if you have the love bangle equipped (or whatever it's called)

as soon as his friendship points are above 100, the door won't be locked to you anymore.

it's also the same with many other locked doors. for example, to get upstairs in the back of the bar, you need either griffin or muffy to have more than 100 friend points.

by the way, when the event with the mermaid happens and you are given the option to tell her daryl will experiment on her, don't tell her that, because it's actually not true.

oh, i almost forgot... there is a small ..cheat.. you can employ to help you out here. usually after you've shown/gifted a person two times, their friendship level will not change. however, EVERYtime you show either your cat or your dog, their points will go up by 1