You Do Need power plug adapter while traveling from Sierra Leone to Syria.

Here is Why You Need An Adapter

The outlet and plug type used in Syria are C, E and L and in Sierra Leone are D and G. This is how they look like.

Sierra Leone

In Sierra Leone, outlets of type D and G are in use.

Type D

Type G

Syria

In Syria, outlets of type C, E and L are in use.

Type C

Type E

Type L