We present the first measurements of very energetic (112-157 keV) 0+ ions in the earth's magnetosphere. The observations were made with the UMd/MPE ULECA sensor on ISEE-1 on 5 March 1981 at geocentric distances ~20 RE in the earth's magnetotail. During this time period an Energetic Storm Particle event was observed by our nearly identical sensor on the ISEE-3 space-craft, located ~250 RE upstream of the earth's magnetosphere. The ISEE-1 sensor observed a similar temporal profile except for several sharp intensity enhancements, corresponding to substorm recoveries during which the plasma sheet engulfed the spacecraft. During these plasma sheet encounters we observe 0+/H+ abundance ratios, at ~130 keV, as large as 0.35. In between plasma sheet encounters with 0+/H+ ratio at this energy is consistent with zero.