Shin Kidou Senki Gundam W: Blind Target

After the war that took place in A.C. 195, each of the protagonists have gone on with their lives, and the gundams put into retirement. As the peace alliance with the colonies push through, a new menace threatens to shatter the peace, and the five gundam pilots are forced into action once again.
Blind Target is originally a radio drama that got translated into manga. It is one of the possible events that took place between the series itself and the OVA, Endless Waltz.
Other manga titles that also delve into the possible events between the series and the OVA are Battlefield of Pacifists and Ground Zero. All three remain unrelated to one another.