The Invisible Ones is Stef Penney's follow up to her acclaimed debut novel The Tenderness of Wolves. It opens with private investigator Ray Lovell in the hospital recovering from a brush with death via an unidentified poisonous substance. The hospital staff suspects that it may have been self-administered, but as Ray swims through strange, frightening hallucinations and recovers his mobility from partial paralysis, he starts to think that his near death might be connected to his investigation into the disappearance and possible murder of a newly married Romany woman several years back.The story unfolds as a dual narrative that follows Ray as he is contacted by Leon Wood. Wood chooses him to investigate the disappearance of his daughter because of Ray’s partial Gypsy heritage. The other perspective is JJ's, a 14-year-old Romany boy who is a part of the family that Ray is investigating. The Invisible Ones carefully details the lives and views of modern day Gypsy families, but the story itself is slow moving. Set in 1980's England, Penney's Ray Lovell is an old school investigator, complete with notebooks and knocks on the door to get his man. Subplots dealing with Lovell's emotional state after the dissolution of his marriage, and how he met his partner provide additional perspective on his character. The novel picks up in the last third to reveal a surprising host of secrets whose huge implications are only vaguely hinted at and barely explored. Some of them were more easily guessed than others.Those interested in the Romany way of life will find Penney's work both thoughtful and fascinating since her portrayal is so crystal clear - details on marriages and retaining "pure" blood, the struggles of the older generations to hold on to the traveling lifestyles and traditions, choosing campsites, and the hierarchies established in home ownership and displays of status provided insight for me in a culture with which I am not familiar. Oftentimes JJ provided the most poignant moments in the novel as his attempts to fit in at school fall short, and as his stress about his cousin sick with the "family" disease and the possible skeletons in the family closet grows. Penney has turned out a solid literary mystery, but better pacing and follow up in the aftermath would have made this a more worthwhile and enjoyable read for me.