Something is causing Martin's metabolism to go haywire. In succession, he loses control of his levitation finger, he magnetizes his clothing, he levitates, he becomes electrically charged, he shrinks and then he disappears. He finds out the cause is an increased activity of sunspots, and on Earth there is no way to control their effects on Martians. After five days, the sunspots are still occurring and Martin is still invisible. The authorities, based on a recent insurance policy Mrs. Brown sold Martin with Tim as beneficiary, suspect that Martin's "disappearance" is due to Tim killing him for the insurance money. Circumstantial evidence points in that direction. Martin can't let Tim go to jail for this, and Martin decides to tell the authorities the truth about his Martian identity. Just then, the sunspots cease and Martin reappears, just in time to save Tim and protect his own identity. (thetvdb.com)