You Do Need power plug adapter while traveling from American Samoa to Bhutan.

Here is Why You Need An Adapter

The outlet and plug type used in Bhutan are C, D and G and in American Samoa are A, B, F and I. This is how they look like.

American Samoa

In American Samoa, outlets of type A, B, F and I are in use.

Type A

Type B

Type F

Type I

Bhutan

In Bhutan, outlets of type C, D and G are in use.

Type C

Type D

Type G