You Do Need power plug adapter while traveling from British Virgin Islands to Bhutan.

Here is Why You Need An Adapter

The outlet and plug type used in Bhutan are C, D and G and in British Virgin Islands are A and B. This is how they look like.

British Virgin Islands

In British Virgin Islands, outlets of type A and B are in use.

Type A

Type B

Bhutan

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

Type C

Type D

Type G