Timeslip was a popular children's adventure serial in 26 parts. It told the complex tale of two teenagers, Liz Skinner and Simon Randall, who find they share the unique ability to project themselves into either the past or the future. Their exploits take them to a World War II naval station, an Antarctic research base in 1990, a tropical jungle in an alternate 1990 Britain and, finally, a government science project in 1965.  Uniquely the series tackled some heavy issues for a "mere" children's series - some of which (like cloning, global warming and laser tracking defense systems) were years (or decades) ahead of their time.