Dragon’s Grace (Sons of Pendragon, book 1)

Sons of Pendragon – Seven brothers with secrets, taken from their own time and raised in the present to continue their father’s work. All they require are the weapons their father gave them as children.
Keepers – Seven women with a secret mission. Each the eldest female in a line of women charged with guarding special weapons through the centuries until their owners appear.
Haunted by a past that only a rare few know, Brennan Pendragon and his brothers hide their real identities. To the outside world, they are co-owners of Pendragon Alliance, a prestigious investigation firm that also deals in protection and retrieval. Injured on his last mission, one that nearly killed him, Brenn is in denial. He does not want to deal with the aftermath. Carnage. Deaths. The sudden, unexpected guardianship of an infant that he does not know what to do with. A baby he wants nothing to do with.
When she’s asked to enter into a marriage of convenience, Grace Rutledge barely hesitates. After all, she has been in love with Brenn from the moment she went to work for his family firm.
Letting Grace into his life turns it upside down. Soon the marriage of convenience is anything but. As Grace begins to heal old wounds and teach him to open his heart once more, Brenn fears ancient enemies may once more rip away all he holds dear. Little does Brenn know that Grace’s and his secrets are already entwined and the danger has just begun.

While part of a series, this is a stand-alone book with no cliffhanger, and a HEA.