We present a multi-wavelength Based on observations obtained with the NASA/ESA Hubble Space Telescope , which is operated by the Space Telescope Science Institute ( STScI ) for the Association of Universities for Research in Astronomy , Inc. , under NASA contract NAS5D26555 , and on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere , Chile under Program ID 085.C - 0172 ( A ) . study of the Magellanic Stream ( MS ) , a massive gaseous structure in the Local Group that is believed to represent material stripped from the Magellanic Clouds . We use ultraviolet , optical and radio data obtained with HST /COS , VLT/UVES , FUSE , GASS , and ATCA to study metal abundances and physical conditions in the Stream toward the quasar Fairall 9 . Line absorption in the MS from a large number of metal ions and from molecular hydrogen is detected in up to seven absorption components , indicating the presence of multi-phase gas . From the analysis of unsaturated S ii absorption , in combination with a detailed photoionization model , we obtain a surprisingly high \alpha abundance in the Stream toward Fairall 9 of [ S/H ] = -0.30 \pm 0.04 ( 0.50 solar ) . This value is 5 times higher than what is found along other MS sightlines based on similar COS/UVES data sets . In contrast , the measured nitrogen abundance is found to be substantially lower ( [ N/H ] = -1.15 \pm 0.06 ) , implying a very low [ N/ \alpha ] ratio of -0.85 dex . The substantial differences in the chemical composition of MS toward Fairall 9 compared to other sightlines point toward a complex enrichment history of the Stream . We favour a scenario , in which the gas toward Fairall 9 was locally enriched with \alpha elements by massive stars and then was separated from the Magellanic Clouds before the delayed nitrogen enrichment from intermediate-mass stars could set in . Our results support ( but do not require ) the idea that there is a metal-enriched filament in the Stream toward Fairall 9 that originates in the LMC .