You Do Need power plug adapter while traveling from Lesotho to Congo.

Here is Why You Need An Adapter

The outlet and plug type used in Congo are C, D and E and in Lesotho is M. This is how they look like.

Lesotho

In Lesotho, outlets of type M are in use.

Type M

Congo

In Congo, outlets of type C, D and E are in use.

Type C

Type D

Type E