The Spacetime War by Les Johnson is a space opera stand-alone.
On leave from the British Commonwealth Space Navy, Captain Winslow Price he decided to take a cruise on a space cruiser. When the ship a crew attempts a hijacking, he is in the right place to help. Also on board and having the same idea as him - to secure the engine to disable the ship so authorities can find them - India Space Force Captain Anika Ahuja has already taken out a couple of the hostiles.
When an unknown ship attacks a colony world, both captains will find themselves at war with an unknown enemy who is apparently bent on taking out all human life in the universe.
Johnson has written a great space opera with the feel of an Honor Harrington / Manitcore novel from David Weber. Fans of science fiction, buy this book today!
Johnson, Les. (2021). The Spacetime War. New York: Baen.