TimeTripper

TimeTripper is a series of science fiction books by Stefan Petrucha following Harry Keller, a teenager who can see time itself and his love interest Siara Warner, who helps him through some tough situations. Harry, not always aware of the significance of events, travels between linear time and A-Time to fix the outcome of events in the lives of others.
Plot.
TimeTripper 1: Yestermorrow.
Siara Warner, a high school junior, becomes attracted to a fellow student, Harry Keller, after witnessing him prevent a shooting, seemingly by accident. Harry, in fact, has been given the ability to see time beyond its linear form, and used this ability to change the future. As he is still getting a handle on the ability, which, as he is well-aware, could also be the manifestation of schizophrenia or another mental illness. After he reaches a plain of existence he calls A-Time, he nevertheless decides to take his ability as truth. However, while navigating this new universe, where every moment co-exists simultaneously, Harry detects a temporal anomaly involving a school outcast. Meanwhile, he semi-successfully explains his condition to Siara, who believes him insane until he successfully brings her into A-Time, where both struggle to prevent predestined events from occurring. "Yestermorrow" was published in 2006.
TimeTripper 2: InRage.
After a series of apparently random occurrences of public violence, Harry discovers that in A-Time, anger is being transmitted from person like a disease, resulting in violent events in reality. Additionally, the level of rage increases with each infection, causing progressively more violent outbursts in the high school population. As Harry tries to come up with a way to stop the chain of rage, Siara also attempts to mend their relationship, and a psychologist attempts to get Harry put back in a mental institution. "InRage" was published in 2006.
TimeTripper 3: BlindSighted.
Finally resigned to the fact that his crush is dating his worst enemy, Harry falls for another girl, Elijah, who is attracted to him. After he begins seeing glimpses of a warehouse fire in the future which will kill numerous people, Harry deduces that a single individual, capable of manipulating A-Time as he is, has been causing the abnormal temporal occurrences thus far. He employs the help of Elijah, who he teaches about A-Time. Meanwhile, Siara attempts to repair their friendship as her suspicions towards Elijah grow. "BlindSighted" was published in 2006.
TimeTripper 4: FutureImperfect.
Harry, drugged, delirious, and trapped in Windfree mental hospital, is incapable of entering A-Time, and though he knows the identity of the ' 'Daemon' ', he is dismissed as insane by his few visitors. After his mind is inexplicably brought back to A-Time despite the hospital medication, he is informed by a mysterious Archetype form about the finer points of reality. Following this, Harry successfully breaks free from the hospital and struggles to prevent the Daemon from inciting another disastrous event. "FutureImperfect" was published in 2007.