Alan Renquist—High school teacher who remembers Perry. Both Alan and his wife, Gayle, are active in sheltering and teaching Penna how to live on Earth.
Barmeth—An alien from the planet Gatton who follows Penna in the cosmic storm and helps her get to the people who can support her when she gets to Earth. Barmeth's spaceship is noted for its marking, which looks like deep red Lazy L. He and his wife, Kaggla, occasionally check on Penna to ensure she is all right. Barmeth fixes a glitch in Penna's citizenship records left by Roger, but at great risk to himself.
Belinda (Richardson) Battistelli—Steve Richardson's sister. Was a clerk at the fabric store Jennifer Wilson managed, and knew of the date Jennifer had with Perry, which never happened after Perry was swept away from Earth.
Cindy Fairchild—Mathematics and computer science teacher who knew both Alan and Gayle, and also Perry before he disappeared. Cindy had since become active in her church, and was well known for taking in wayward young women and helping them get back on their feet.
Jenna—Penna's Nenmaran mother.
Jennifer (Wilson) Martin—Owns and operates a regional chain of fabric stores. Was Jennifer Wilson when Perry had asked her out; only when she sees Penna does she realize what happened to Perry 20 years ago.
John Rosser, Jr.—John and Peggy's son. Returned from his upscale home in suburban Connecticut to settle his father's estate, and to visit his aging mother who has a live-in care giver. It was on the senior Rossers' property that the cosmic storm caught Perry; Peggy had never forgotten.
Kaggla—An alien from the planet Gatton who is a biological scientist, traveling about the galaxy synthesizing new and useful lifeforms. She and her husband, Barmeth, help Penna a number of times. Kaggla briefs Bob and Shirley on what she had learned from her genetic study of Penna's body samples; Kaggla knows Earth medical terminology well enough to communicate it effectively in English to the two Earth doctors.
Karen Bennett—Lyle's wife, who accepts his story of chasing the UFO as something he believes, but is not sure it really happened until she meets Penna much later in life. Karen is not able to have children of her own, focuses her attention on her husband and her real estate business.
Lyle Bennett—Fighter pilot who chases the Lazy L spaceship. He later finds depressions in the ground with the same Lazy L markings. He tells no one for fear of losing his security clearance. He later discovers who Penna is and becomes friends with her and her family. Lyle is divorced from his first wife, Wanda, and rarely sees his children.
Marsha (Perry) Thompson—Perry's (Nennef's) and Susan's mother, Penna's grandmother, and William (Bill) Thompson's wife. She is a language arts professor at the local college.
Melissa (Missy) (Rodriguez) Richardson—Remembers Perry and is one of the few who realize who Penna really is. Married to Steve Richardson, Missy saw with Steve the cosmic storm just before if caught Perry (in Earth Alien).
Nancy Borg—Lab technician at the college and a friend of Penny's (Penna) until she figures out that Penna is a space alien; then she threatens Penna with a letter opener. Nancy later has a tense encounter with Kaggla as she discovers Kaggla and Penna in the lab late at night; Nancy has a gun and considers killing them both on the spot.
Penna (Penny)—Perry's daughter, born on the planet Nenmar (in Earth Alien), swept to Earth by the same cosmic storm that swept her father, Perry Thompson, from Earth to Nenmar. Penna writes and speaks English, but with a strange soft accent. She adopts the name Penny to help her assimilate better. A select, perceptive, few realize who Penna is: a space alien with human blood relatives on Earth; each person protects Penna's secret.
Perry Thompson—Penna's father, known on Nenmar as Nennef. Penna learns about his childhood and early adulthood before he was taken from Earth by the cosmic storm.
Richard (Ricky) La Beaux—Penna's husband. Ricky is deaf, and Penna learns sign language as a result of meeting him. They begin dating in earnest and Penna learns in-hand signing so she can talk with Ricky in the dark when he cannot see. Ricky is thrilled and accepting of Penna being from a different world. He learns all he can about Nenmar, but keeps it to himself, as none of Penna's other support group knows sign language.
Robert (Bob) Carter—A general practice M.D. who is the Renquists and Peggy Rosser's physician. From south Georgia and of African American descent, Bob is married to Shirley Mendicott.
Roger Benson—A professional computer hacker and one of Susan's boyfriends du jour. He is obnoxious and insulting to Penna. He is instrumental in getting Penna her citizenship papers, but deliberately leaves a glitch in her digital records.
Sennef—Penna's brother from their human father and Nenmaran mother. Although she has not seen Sennef since she was taken to Earth, Penna remains close to her brother.
Shirley (Mendicott) Carter—An Ob/Gyn physician who has Gayle Renquist and Peggy Rosser among her patients. From an upper middle class family in the same neighborhood as John Rosser, Jr., Shirley has adventurous inclinations. She is married to Bob Carter.
Stan Desslin—The public works supervisor for the suburban county where the story takes place. Penna learns from Stan how the utilities work, and warns him from her own visual observations of storm damage to a new subdivision's drainage system. Penna and Stan are friends, but he never knows about her secret of being a space alien.
Susan Thompson—Perry's little sister, and Penna's Aunt Susan. She never marries, but has an endless string of live-in boyfriends. Susan is a significant factor in Penna's life.
William (Bill) Thompson—Perry's father and Penna's grandfather. He is head of the natural science department at the local college. Bill is married to Marsha Perry.
