Calvin Hobbes Time Traveler

We have failed our mission.  I am the last of myself that has been sent back.  Each time we have been sent back to the beginning of our mission, we were able to obtain the object we were sent to obtain, along with the knowledge needed to save our world.  Each time we attempt to return home we are drawn to this timeline.
When the first of us was stranded here he landed from a different time than the second one.  The second one landed earlier than the first.  He waited, hiding for eighteen months, for the arrival of the first of us.  The two met, discussed the details of the mission and realized there will be others.  We needed to be able to communicate with each other in some way, in case we were not able to find the current one of us before time took its course.

There can not exist more than two versions of oneself at one time.  If one of those versions is your younger self then any self that appears after is up for elimination.  Time will not allow a third to exist for very long.

I have studied all the post from my previous selves and have brought back copies for the other selves to find and post them.  We can not save our world by going home so I have decided that the only way to save my future is to change your past.

After I am gone my complete writings will be posted for the world to see.  Hopefully I have made enough changes to the timeline that my future does not come to pass.  Hopefully she is safe.

I do not have much time left before I too disappear.  I am the last of myself to be sent back and I am the first to arrive in your timeline.  My name is Calvin and this is my story…