Ink and Ashes, by Valynne E. Maetani (Tu Books, June 2015) assuming it was speculative fiction, as that's what I associate with Tu Books. So my reading experience was colored by the expectation that at an minute, supernatural forces would appear...but this never happened. Instead, Ink and Ashes is more a mystery/thriller type book.
Claire is an ordinary Japanese/American teenager, with a loving family--mother, stepfather (her own father having died when she was seven) and two brothers. Three more neighborhood boys are almost family too, including her best friend, Forrest. But when Claire finds a letter, in Japanese, hiding among some old papers belonging to her biological father, she sets in train a disaster when secrets from her father's past as a member of the Japanese mafia come back to haunt her family, with potentially deadly consequences. Claire finds herself the target of progressively more frightening threats, and though her stepfather promises to do his best to keep her safe, Claire can't help what wonder what other secrets he himself is hiding....
And in the meantime, Forrest becomes more than just a best friend!
So the mystery is combined with a romance, and readers will enjoy following the trail of clues along with Claire and her brothers and friends. Claire's relationship with the back of boys brings warmth and humor to the mystery, and elements of Japanese culture and Claire's own experience of being Japanese/American add interest. Although the mystery itself, which hinges on Claire's parents withholding information and Claire withholding information of her own from them, didn't entirely work for me, this is possibly because I was expecting demons or something.
Short answer: a good read for those who enjoy teens under threat from mysterious strangers who want to kill them.