The Longest Day - Ark Royal, #10

A Stand-Alone Novel Set In The Ark Royal Universe!The first major alien offensive against Earth has been blunted, winning humanity time to deploy new weapons and prepare new tactics as Earth's space navies prepare to take the offensive.  But the enigmatic aliens have plans of their own - a full-scale attack on Earth that will either win the war in a single stroke or lose it. The stakes have never been so high.  The fate of humanity itself is in the balance.  And, as battle rages across the solar system, as humanity finds its back pushed firmly against the war, millions of people - military and civilian - struggle for survival, knowing that victory will come with a very high price ......
And defeat will be the end of everything humanity holds dear.